Current working FGD entries (paste these into your portal 2 fgd file to have them in hammer):

@PointClass base(Parentname, Targetname, Angles) studio( "models/npc/hover_turret.mdl" ) = npc_hover_turret: "Hover Turret."

[
	attachTarget(string) : "attachTarget" : "" : "The attach Target"

	// Inputs
	input InteractivePowerDown(void)
	input CreateAddon(string)
	input UpdateEnemyMemory(string)
	input ForceInteractionWithNPC(string)
	input UnholsterWeapon(void)
	input HolsterAndDestroyWeapon(void)
	input HolsterWeapon(void)
	input SetSpeedModSpeed(integer)
	input SetSpeedModRadius(integer)
	input DisableSpeedModifier(void)
	input ActivateSpeedModifier(void)
	input OutsideTransition(void)
	input InsideTransition(void)
	input GagDisable(void)
	input GagEnable(void)
	input StopScripting(void)
	input StartScripting(void)
	input Break(void)
	input IgnoreDangerSounds(float)
	input ForgetEntity(string)
	input Wake(void)
	input SetSquad(string)
	input BeginRappel(void)
	input SetHealth(integer)
	input SetEnemyFilter(string)
	input SetRelationship(string)
	input KilledNPC(void)
	input physdamagescale(float)
	input SetLightingOrigin(string)
	input SetLightingOriginHack(string)
	input BecomeRagdoll(void)
	input IgniteHitboxFireScale(float)
	input IgniteNumHitboxFires(integer)
	input IgniteLifetime(float)
	input Ignite(void)
	input SetBodyGroup(integer)
	input skin(integer)
	input RemovePaint(void)
	input CallScriptFunction(string)
	input RunScriptCode(string)
	input RunScriptFile(string)
	input FireUser4(string)
	input FireUser3(string)
	input FireUser2(string)
	input FireUser1(string)
	input AddOutput(string)
	input EnableDrawInFastReflection(void)
	input DisableDrawInFastReflection(void)
	input EnableReceivingFlashlight(void)
	input DisableReceivingFlashlight(void)
	input EnableDraw(void)
	input DisableDraw(void)
	input EnableShadow(void)
	input DisableShadow(void)
	input ClearContext(string)
	input RemoveContext(string)
	input AddContext(string)
	input DispatchResponse(string)
	input DisableDamageForces(void)
	input EnableDamageForces(void)
	input SetDamageFilter(string)
	input SetLocalAngles(string)
	input SetLocalOrigin(string)
	input ClearParent(void)
	input SetParentAttachmentMaintainOffset(string)
	input SetParentAttachment(string)
	input SetParent(string) : "Changes the entity's parent in the movement hierarchy."
	input AlternativeSorting(boolean)
	input Alpha(integer)
	input Use(void)
	input KillHierarchy(void)
	input Kill(void)
	input fademaxdist(float)
	input fademindist(float)
	input SetTeam(integer)
	input TeamNum(integer)

	// Outputs
	output OnAlyxFinishedInteraction(void)
	output OnAlyxStartedInteraction(void)
	output OnPhysGunDrop(void)
	output OnPhysGunPickup(void)
	output OnForcedInteractionFinished(void)
	output OnForcedInteractionAborted(void)
	output OnForcedInteractionStarted(void)
	output OnSleep(void)
	output OnWake(void)
	output OnRappelTouchdown(void)
	output OnDenyCommanderUse(void)
	output OnDamagedByPlayerSquad(void)
	output OnDamagedByPlayer(void)
	output OnHearCombat(void)
	output OnHearPlayer(void)
	output OnHearWorld(void)
	output OnLostPlayer(void)
	output OnLostPlayerLOS(void)
	output OnFoundPlayer(void)
	output OnLostEnemy(void)
	output OnLostEnemyLOS(void)
	output OnFoundEnemy(void)
	output OnHalfHealth(void)
	output OnDeath(void)		:	"Fired after this turret finishes it's destroy think and begins it's death think."
	output OnDamaged(void)
	output OnFizzled(void)
	output OnIgnite(void)
	output OnUser4(void)
	output OnUser3(void)
	output OnUser2(void)
	output OnUser1(void)


]

@PointClass base(Targetname,Parentname,Angles) studio("models/editor/axis_helper_thick.mdl") = ent_hover_turret_tether :
"Tether that hover turrets attach to."
[

	// Inputs
	input SetLightingOrigin(string)
	input SetLightingOriginHack(string)
	input BecomeRagdoll(void)
	input IgniteHitboxFireScale(float)
	input IgniteNumHitboxFires(integer)
	input IgniteLifetime(float)
	input Ignite(void)
	input SetBodyGroup(integer)
	input skin(integer)
	input RemovePaint(void)
	input CallScriptFunction(string)
	input RunScriptCode(string)
	input RunScriptFile(string)
	input FireUser4(string)
	input FireUser3(string)
	input FireUser2(string)
	input FireUser1(string)
	input AddOutput(string)
	input EnableDrawInFastReflection(void)
	input DisableDrawInFastReflection(void)
	input EnableReceivingFlashlight(void)
	input DisableReceivingFlashlight(void)
	input EnableDraw(void)
	input DisableDraw(void)
	input EnableShadow(void)
	input DisableShadow(void)
	input ClearContext(string)
	input RemoveContext(string)
	input AddContext(string)
	input DispatchResponse(string)
	input DisableDamageForces(void)
	input EnableDamageForces(void)
	input SetDamageFilter(string)
	input SetLocalAngles(string)
	input SetLocalOrigin(string)
	input ClearParent(void)
	input SetParentAttachmentMaintainOffset(string)
	input SetParentAttachment(string)
	input SetParent(string)
	input AlternativeSorting(boolean)
	input Alpha(integer)
	input Use(void)
	input KillHierarchy(void)
	input Kill(void)
	input fademaxdist(float)
	input fademindist(float)
	input SetTeam(integer)
	input TeamNum(integer)

	// Outputs
	output OnFizzled(void)
	output OnIgnite(void)
	output OnUser4(void)
	output OnUser3(void)
	output OnUser2(void)
	output OnUser1(void)
]



/////////////////////////////////////////////////////////

Original full keyvalues/IOs (these still need to be fixed before they will work in Hammer. Feel free to get them all working and send them to me!)

@PointClass = ent_hover_turret_tether
	[
	SuppressAnimSounds(boolean) : "SuppressAnimSounds"
	ModelScale(float) : "ModelScale"
	LightingOrigin(string) : "LightingOrigin"
	LightingOriginHack(string) : "LightingOriginHack"
	cycle(float) : "cycle"
	playbackrate(float) : "playbackrate"
	sequence(integer) : "sequence"
	hitboxset(integer) : "hitboxset"
	SetBodyGroup(integer) : "SetBodyGroup"
	body(integer) : "body"
	skin(integer) : "skin"
	ModelSkin(integer) : "ModelSkin"
	LagCompensate(boolean) : "LagCompensate"
	fadescale(float) : "fadescale"
	fademaxdist(float) : "fademaxdist"
	fademindist(float) : "fademindist"
	spawnflags(integer) : "spawnflags"
	texframeindex(integer) : "texframeindex"
	velocity(vector) : "velocity"
	ltime(float) : "ltime"
	friction(float) : "friction"
	gravity(float) : "gravity"
	waterlevel(integer) : "waterlevel"
	avelocity(vector) : "avelocity"
	basevelocity(vector) : "basevelocity"
	addon(string) : "addon"
	model(studio) : "model"
	teamnumber(integer) : "teamnumber"
	TeamNum(integer) : "TeamNum"
	shadowcastdist(float) : "shadowcastdist"
	CollisionGroup(integer) : "CollisionGroup"
	MoveType(integer) : "MoveType"
	solid(integer) : "solid"
	damagefilter(string) : "damagefilter"
	target(string) : "target"
	health(integer) : "health"
	ResponseContext(string) : "ResponseContext"
	modelindex(integer) : "modelindex"
	effects(integer) : "effects"
	nextthink(integer) : "nextthink"
	thinkfunction(string) : "thinkfunction"
	vscripts(string) : "vscripts"
	rendermode(integer) : "rendermode"
	renderfx(integer) : "renderfx"
	speed(float) : "speed"
	hammerid(integer) : "hammerid"
	maxgpulevel(integer) : "maxgpulevel"
	mingpulevel(integer) : "mingpulevel"
	maxcpulevel(integer) : "maxcpulevel"
	mincpulevel(integer) : "mincpulevel"
	parentname(string) : "parentname"
	globalname(string) : "globalname"
	classname(string) : "classname"

	// Inputs
	input SetLightingOrigin(string)
	input SetLightingOriginHack(string)
	input BecomeRagdoll(void)
	input IgniteHitboxFireScale(float)
	input IgniteNumHitboxFires(integer)
	input IgniteLifetime(float)
	input Ignite(void)
	input SetBodyGroup(integer)
	input skin(integer)
	input RemovePaint(void)
	input CallScriptFunction(string)
	input RunScriptCode(string)
	input RunScriptFile(string)
	input FireUser4(string)
	input FireUser3(string)
	input FireUser2(string)
	input FireUser1(string)
	input AddOutput(string)
	input EnableDrawInFastReflection(void)
	input DisableDrawInFastReflection(void)
	input EnableReceivingFlashlight(void)
	input DisableReceivingFlashlight(void)
	input EnableDraw(void)
	input DisableDraw(void)
	input EnableShadow(void)
	input DisableShadow(void)
	input ClearContext(string)
	input RemoveContext(string)
	input AddContext(string)
	input DispatchResponse(string)
	input DisableDamageForces(void)
	input EnableDamageForces(void)
	input SetDamageFilter(string)
	input SetLocalAngles(string)
	input SetLocalOrigin(string)
	input ClearParent(void)
	input SetParentAttachmentMaintainOffset(string)
	input SetParentAttachment(string)
	input SetParent(string)
	input AlternativeSorting(boolean)
	input Alpha(integer)
	input Use(void)
	input KillHierarchy(void)
	input Kill(void)
	input fademaxdist(float)
	input fademindist(float)
	input SetTeam(integer)
	input TeamNum(integer)

	// Outputs
	output OnFizzled(void)
	output OnIgnite(void)
	output OnUser4(void)
	output OnUser3(void)
	output OnUser2(void)
	output OnUser1(void)
	]



@PointClass = npc_hover_turret
	[
	canPushPlayer(boolean) : "canPushPlayer"
	sentryRotateSpeed(float) : "sentryRotateSpeed"
	attachTarget(string) : "attachTarget"
	enemyfilter(string) : "enemyfilter"
	additionalequipment(string) : "additionalequipment"
	hintlimiting(boolean) : "hintlimiting"
	hintgroup(string) : "hintgroup"
	squadname(string) : "squadname"
	ignoreunseenenemies(boolean) : "ignoreunseenenemies"
	wakesquad(boolean) : "wakesquad"
	wakeradius(float) : "wakeradius"
	sleepstate(integer) : "sleepstate"
	physdamagescale(float) : "physdamagescale"
	Relationship(string) : "Relationship"
	BloodColor(integer) : "BloodColor"
	HullType(integer) : "HullType"
	SuppressAnimSounds(boolean) : "SuppressAnimSounds"
	ModelScale(float) : "ModelScale"
	LightingOrigin(string) : "LightingOrigin"
	LightingOriginHack(string) : "LightingOriginHack"
	cycle(float) : "cycle"
	playbackrate(float) : "playbackrate"
	sequence(integer) : "sequence"
	hitboxset(integer) : "hitboxset"
	SetBodyGroup(integer) : "SetBodyGroup"
	body(integer) : "body"
	skin(integer) : "skin"
	ModelSkin(integer) : "ModelSkin"
	LagCompensate(boolean) : "LagCompensate"
	fadescale(float) : "fadescale"
	fademaxdist(float) : "fademaxdist"
	fademindist(float) : "fademindist"
	spawnflags(integer) : "spawnflags"
	texframeindex(integer) : "texframeindex"
	velocity(vector) : "velocity"
	ltime(float) : "ltime"
	friction(float) : "friction"
	gravity(float) : "gravity"
	waterlevel(integer) : "waterlevel"
	avelocity(vector) : "avelocity"
	basevelocity(vector) : "basevelocity"
	addon(string) : "addon"
	model(studio) : "model"
	teamnumber(integer) : "teamnumber"
	TeamNum(integer) : "TeamNum"
	shadowcastdist(float) : "shadowcastdist"
	CollisionGroup(integer) : "CollisionGroup"
	MoveType(integer) : "MoveType"
	solid(integer) : "solid"
	damagefilter(string) : "damagefilter"
	target(string) : "target"
	health(integer) : "health"
	ResponseContext(string) : "ResponseContext"
	modelindex(integer) : "modelindex"
	effects(integer) : "effects"
	nextthink(integer) : "nextthink"
	thinkfunction(string) : "thinkfunction"
	vscripts(string) : "vscripts"
	rendermode(integer) : "rendermode"
	renderfx(integer) : "renderfx"
	speed(float) : "speed"
	hammerid(integer) : "hammerid"
	maxgpulevel(integer) : "maxgpulevel"
	mingpulevel(integer) : "mingpulevel"
	maxcpulevel(integer) : "maxcpulevel"
	mincpulevel(integer) : "mincpulevel"
	parentname(string) : "parentname"
	globalname(string) : "globalname"
	classname(string) : "classname"

	// Inputs
	input InteractivePowerDown(void)
	input CreateAddon(string)
	input UpdateEnemyMemory(string)
	input ForceInteractionWithNPC(string)
	input UnholsterWeapon(void)
	input HolsterAndDestroyWeapon(void)
	input HolsterWeapon(void)
	input SetSpeedModSpeed(integer)
	input SetSpeedModRadius(integer)
	input DisableSpeedModifier(void)
	input ActivateSpeedModifier(void)
	input OutsideTransition(void)
	input InsideTransition(void)
	input GagDisable(void)
	input GagEnable(void)
	input StopScripting(void)
	input StartScripting(void)
	input Break(void)
	input IgnoreDangerSounds(float)
	input ForgetEntity(string)
	input Wake(void)
	input SetSquad(string)
	input BeginRappel(void)
	input SetHealth(integer)
	input SetEnemyFilter(string)
	input SetRelationship(string)
	input KilledNPC(void)
	input physdamagescale(float)
	input SetLightingOrigin(string)
	input SetLightingOriginHack(string)
	input BecomeRagdoll(void)
	input IgniteHitboxFireScale(float)
	input IgniteNumHitboxFires(integer)
	input IgniteLifetime(float)
	input Ignite(void)
	input SetBodyGroup(integer)
	input skin(integer)
	input RemovePaint(void)
	input CallScriptFunction(string)
	input RunScriptCode(string)
	input RunScriptFile(string)
	input FireUser4(string)
	input FireUser3(string)
	input FireUser2(string)
	input FireUser1(string)
	input AddOutput(string)
	input EnableDrawInFastReflection(void)
	input DisableDrawInFastReflection(void)
	input EnableReceivingFlashlight(void)
	input DisableReceivingFlashlight(void)
	input EnableDraw(void)
	input DisableDraw(void)
	input EnableShadow(void)
	input DisableShadow(void)
	input ClearContext(string)
	input RemoveContext(string)
	input AddContext(string)
	input DispatchResponse(string)
	input DisableDamageForces(void)
	input EnableDamageForces(void)
	input SetDamageFilter(string)
	input SetLocalAngles(string)
	input SetLocalOrigin(string)
	input ClearParent(void)
	input SetParentAttachmentMaintainOffset(string)
	input SetParentAttachment(string)
	input SetParent(string)
	input AlternativeSorting(boolean)
	input Alpha(integer)
	input Use(void)
	input KillHierarchy(void)
	input Kill(void)
	input fademaxdist(float)
	input fademindist(float)
	input SetTeam(integer)
	input TeamNum(integer)

	// Outputs
	output OnAlyxFinishedInteraction(void)
	output OnAlyxStartedInteraction(void)
	output OnPhysGunDrop(void)
	output OnPhysGunPickup(void)
	output OnForcedInteractionFinished(void)
	output OnForcedInteractionAborted(void)
	output OnForcedInteractionStarted(void)
	output OnSleep(void)
	output OnWake(void)
	output OnRappelTouchdown(void)
	output OnDenyCommanderUse(void)
	output OnDamagedByPlayerSquad(void)
	output OnDamagedByPlayer(void)
	output OnHearCombat(void)
	output OnHearPlayer(void)
	output OnHearWorld(void)
	output OnLostPlayer(void)
	output OnLostPlayerLOS(void)
	output OnFoundPlayer(void)
	output OnLostEnemy(void)
	output OnLostEnemyLOS(void)
	output OnFoundEnemy(void)
	output OnHalfHealth(void)
	output OnDeath(void)
	output OnDamaged(void)
	output OnFizzled(void)
	output OnIgnite(void)
	output OnUser4(void)
	output OnUser3(void)
	output OnUser2(void)
	output OnUser1(void)
	]


I can be reached at thewolfcl0ck@gmail.com or Wolfcl0ck#2027 on Discord if you have anything to share. Enjoy, and have fun modding!