All script changes, split with proof (*) & speculation/proof points to follow (**). Second txt for reference of dialogue and audio.

MISSIONS:

#1: Change location of Rosenberg's Office/Contact Point
*Unused intro cutscene with cut audio originally with dialogue in reference to office being different location from drop-off (INT4_G-I).
**Contact Point @ (random, like surrounding) building name "wshbuildws09" & cutscene office spot @ (unique, unlike surrounding) name "wslawyersfront".
**BETA screens show "wshbuildws09" to be larger/stretched vertically, odd to see with final model (specifically doorway/mission entry).

#2: Restore BJ Smith debt cut phone call & loan sharks/payment ability
*Unused cellphone dialogue (gxt & wavs) from realtor stating Tommy must pay BJ's unpaid debts for BJ's Used Autos after his disappearance.

#3: Restore Tommy monologue after missions
*Unused monologue audio (wavs) among used ones, all reference existing missions.

#4: Restore cellphone conversations
*Unused dialogue (gxt & wavs) from various cast.
**Pointless to restore Moffat, Avery & some Mercedes phonecalls as the audio doesn't exist, for Moffat, as well as no audio, there's no model, texture, or mission leftovers exist, & for Avery, there's no audio & Gator Keys doesn't exist either.
**First noted phone call from Ken about business may be an introduction to asset pick-ups.

#5: Restore cut dialogue in Back Alley Brawl
*Unused dialogue (gxt & wavs) from Lance.
**First few bits of dialogue presumably when the player crashes Lance's car & gets out before getting to the objective.
**Suggested by latter dialogue, it's possible that the Pole Position Club was always open, later in development closed to make it a property?

#6: Restore dialogue in The Party about motorcycle
*Unused dialogue (gxt & wavs) about pedestrian's motorcycle.
**Presumed that this is from after Soiree outfit change, with guy staying on motorcycle as woman comes up & chats - resulting in Tommy punching him off & stealing, or guy getting off motorcycle & chatting to a woman as Tommy steals it.

#7: Restore MC Tommy pickup to Howlin' Petes
*The only unused clothing store is Howlin' Petes, which is biker-oriented.
*MC Tommy is a cut outfit, with the GXT entry for "MC Tommy" & a 13th entry for clothing pickups with the MC Tommy tag still existing.
**Most likely made available after the first or all biker missions?

#8: Restore cut dialogue in The Job.
*Unused dialogue (wavs) said by Tommy, Cam & Phil.
**ABC lines presumed to either be used upon mission failure & restart, or for scripter's choice to use.

#9: Restore cut dialogue & sleeping cop in No Escape?
*Unused dialogue (wavs) said by cops.
*A random snoring sound is heard, with no cop in sight.
**Dialogue is presumed to have been said as the player enters, if the player starts shooting up the place after getting the outfit, trespasses without an outfit, & unlocks Cam's cell.
**Presumably the scene was supposed to indicate that the cop had fallen asleep either with the outfit out, with the player taking it, or simply undressing him & taking the outfit whilst sleeping.

#10: Remake Steve Scott stunt mission (mob11)?
*Unused audio & GXT entries left over for a phone call by Steve asking Tommy to do a chase scene at the airport.
**Not much point in restoring this phonecall, as you'd have to remake the chase out of pure guessing & fans may not like that.

#11: Restore Avery in Bar Brawl?
*PS2 IFP of this cutscene shows that Avery was in this cutscene, however the developers placed him far away.

#12: Restore yt_gangplnk_tmp to All Hands On Deck! cutscene
*Tommy & The Colonel walk up an invisible bridge to the ship, which is where this was most likely supposed to go.

#13: Restore Supply & Demand cutscene & cut dialogue
*Unused dialogue (wavs) said by Lance & Tommy, & wavs + ifp for cutscene in the middle of Supply & Demand

#14: Remake the old Sunshine Autos Race 6 route
*The map for the Sunshine Autos Race 6 route is different than the route in the actual race.

#15: Restore Garbage Truck missions?
*GXT entry for a Garbage pickup count stat still exists.

#16: Restore cut dialogue in Rub Out.
*Unused dialogue (wavs) said by Lance & Tommy.
**Assumed to be said when either character is on low health or generally taking damage, last cut line most likely said when player goes to the mansion garden (back), or maybe if they go to the maze (right)?

#17: Restore cut dialogue in Alloy Wheels of Steel.
*Unused dialogue (wavs) said by random biker.
**Most likely said by fellow racer upon winning or losing.

#18: Restore cut dialogue in Spilling the Beans.
*Unused dialogue (wavs) said by random guard.
**Probably exclaimed as the player makes his way upon & along the ship.

#19: Restore cut dialogue in The Chase.
*Unused dialogue (wavs) said by the chased & Tommy.
**First line most likely said as or after the chased jumps off the building, and the second after Tommy gets on the Faggio.

#20: Restore cut dialogue in Phnom Penh '86.
*Unused dialogue (wavs) said by Lance & Tommy.
**Last couple of lines presumably to add more to the mission than silence/shooting. Perhaps a rock song? Anything suitable for shooting.

#21: Restore cut dialogue in The Fastest Boat.
*Unused dialogue (wavs) said by Jethro w/ last line by a guard?
**Presumably Jethro would be unkillable in this, wherever he is, to keep the Boatyard asset cutscene canon.

#22: Restore cut dialogue in Guardian Angels.
*Unused dialogue (wavs) said by Lance & Diaz.
**First line presumably needing no gxt entry, with the text shown most likely being a reminder of the objective.
**Later two lines being for if the player deals damage to Lance or Diaz? Last one maybe being for when the bikers steal the money?

#23: Restore cut dialogue in Sir, Yes, Sir!
*Unused dialogue (wavs) said by soldiers & tank A.I.
**Not sure how self-destruct would work? Perhaps a timer for getting the Tank to the garage? But doesn't really make sense for it not to still blow up after placing in the garage.
**Maybe make the self-destruct initiation be toggled via the horn button?

#24: Restore cut dialogue in All Hands on Deck!
*Unused dialogue (wavs) said by Colonel & one of his fellow men.

#25: Restore cut dialogue in Keep Your Friends Close.. & move Sonny from the entrance to Tommy's office
*Unused dialogue (wavs) said by Tommy.
**Suggested by fin_6, perhaps after coming back from killing Lance, Sonny had moved to Tommy's office instead of being at the entrance?

#26: Restore cut dialogue in Waste the Wife.
*Unused dialogue (wav) said by the Wife.
**Presumably said when smashing into her car.

#27: Restore cut dialogue in Jury Fury.
*Unused dialogue (gxt & wavs) said by Jury members & Tommy.
**Jury members most likely noticing that Tommy is beating their car up? Or maybe there were more cars to damage?

#28: Restore cut dialogue in Riot.
*Unused dialogue (wavs) said by rioters.
**Presumably said amongst the general rioter ambience.

#29: Restore cut dialogue in Death Row.
*Unused dialogue (wavs) said by guards.
**May be said by guard towards Tommy in the junkyard? Or maybe to Lance as he's sat? Or possibly said by the pursuers when driving to the hospital.

#30: Restore cut dialogue in Love Juice.
*Unused dialogue (wav) said by Tommy.
**Most likely an alternate audio upon mission failure & restart? (Hence tag "1b").

#31: Restore cut dialogue in Friendly Rivalry.
*Unused dialogue (wavs) said by Delores
**First three lines presumably said when the player deals damage to the rival taxis.
**No clue where the last line would apply, maybe VC Cabs had a back-up limousine or something?

#32: Restore cut dialogue in Cabmaggedon.
*Unused dialogue (wav) said by rival taxi drivers
**Presumably said by the Zebra Cab driver, as the Zebra Cab gets close to Tommy after the cutscene.
**Alternatively, may have been the original line in the cutscene with tax3_4 being said in the arrival of the several rival cabs.

#33: Restore cut dialogue in Four Iron.
*Unused dialogue (wavs) said by target & guard.
**First line presumably said either as the player gets dealt damage after getting too close/being spotted, with the second being after the player kills the target.

#34: Restore cut dialogue in Demolition Man.
*Unused dialogue (wav) said by construction workers.

#35: Restore cut dialogue in The Shootist.
*Unused dialogue (wav) said by Phil.
*Line presumably said as the player beats the high score.

#36: Restore cut dialogue in The Driver.
*Unused dialogue (wavs) said by Hilary.

#37: Restore cut dialogue in Cop Land.
*Unused dialogue (wavs) said by Tommy & Lance.
**Presumed to either be used upon mission failure & restart, or for scripter's choice to use.

#38: Swap order of Avery's missions around, Two Bit Hit to be 2nd & Demolition Man to be 3rd/last
*Avery mission order in GXT is SERG1 (Four Iron), SERG2 (Two Bit Hit) & SERG3 (Demolition Man).
*In the "Demolition Man" cutscene, Avery says he's going out of town for a while, yet is immediately back to give Two Bit Hit, with no mention of leaving/returning.

#39: Change initial objective in In the beginning...?
*Several GXT entries all telling the player to find the hotel.

#40: Join An Old Friend & The Party together?
*GXT entry objective telling the player to go to the Lawyer's Office.

#41: Make dates with Mercedes?
*GXT entries indicating rides with Mercedes, and multiple "goodbye" lines.
**Would make sense alongside Mercedes' cut phone calls, possibly some (negative ones) only happening if the player doesn't visit Mercedes?
**Possibly worked as an excitement system? I think something similar to this was in San Andreas?
**Mostly pointless to try & restore this as the audio for Mercedes' comments no longer exist.

#42: Replace Umberto Robina's intro phonecall with the original
*Unused dialogue (gxt & wavs) from Umberto & Tommy.

OPEN-WORLD:

#43: Restore cut dialogue in Strip Club
*Unused dialogue (wavs) said by stripper.
**Presumably said during back room dance, &/or by general strippers walking around.

#44: Restore cut dialogue at the Golf Club
*Unused dialogue (wavs) said by guard at Golf Club upon entering with weapons

#45: Add person outside Star Island gates
*Unused dialogue (wavs) said by guard outside Star Island.
**Perhaps the guard was stood in a shack, similar to the airport gate operator shacks?
**Maybe the Star Island gates were automatically moved, like a garage door, instead of just static/suddenly forever open after certain story point?

#46: Remake ability to rob OTB
*As from the PS2 files, the OTB in Washington had a special txd for an interior. This interior has been remade & so needs to serve some function/reason to exist - like robbery, for example like the jewellery stores.

#47: Make nbsavehotel a buyable property/safehouse
*Unlike the surrounding buildings, this has the specific name of "nbsavehotel".
**Haven't been able to find any unused safehouse names, perhaps make a new name for it after an old mod - like Myriad?

#48: Make Well Stacked Pizza in Washington functional
*According to the LOD, name, & flags of this building, the "washpizzaplace" building in Washington used to be a pizza store like the rest - this has been remade & so needs to have a shop keep & an ability to buy food.
*Pizza Boy missions also need to be available from the side of this place.

#49: Remove Apartment 3c interior marker
*According to pre-release screenshots, the interior was in the overworld, this has been re-done and so the interior entrance check needs removing.

#50: Restore buyable property icon to map/radar
*According to several strategy guide screenshots, the buyable property icon was used for all un-bought properties.
*According to Noskillx, this function should still work (at least for the Malibu) however for some reason it does not. Perhaps replace another unused icon with this to make it function?

#51: Remove First Person Cam for M60
*According to a strategy guide screenshot, the usual target lock was used for this weapon instead of a manual aim.

#52: Remake old Target Circle (pure red circle) (scan.png)
*According to a strategy guide screenshot, the target circle (when locked-on to a ped) was a pure red circle with no extras.

#53: Remove the Stadium [SCM #2]
*According to the superLOD (islandLODMainland), the Stadium did not exist & in its place was a beach, the Stadium has been removed & so the billboards, general entry check, etc. must be removed so the player can still achieve 100%.
*This must be in a split SCM [SCM #2] with the rest of the changes still in, for split audiences who wish to not have it removed.

#54: Remove North Beach RC race [SCM #2]
*According to various pre-release screens & the superLOD (islandLODBeach) the north part of the Beach on the East Island did not exist, in turn the RC Race found there didn't either - the Top Fun van spawn and general check must be removed so the player can still achieve 100%.
*This must be in a split SCM [SCM #2] with the rest of the changes still in, for split audiences who wish to not have it removed.

#55: Remove Bunch of Tools in Washington [SCM #2]
*As seen in pre-release screens, several plain buildings were in the place of the Bunch of Tools building, they have been recreated & so the radar icon and general functionability of the store needs to be removed.
*This must be in a split SCM [SCM #2] with the rest of the changes still in, for split audiences who wish to not have it removed.

#56: Restore bartender dialogue
*Unused dialogue (wavs) said by a female bartender.
**Presumably said by bartender at Malibu Club (& maybe Strip Club) when the player goes up to the bar before the purchase of either.

#57: Remove VCPD Stunt Jump
*According to the superLOD (islandLODBeach), neither bridges connecting the construction sites to the east side of the island existed, this change has been made and so the stunt jump is odd & needs to be removed.

STATS:

#58: Restore Visits from Loan Sharks stat (tie-in from BJ Smith "unfriendly streets"?)
*GXT entry still exists for this stat.

#59: Restore ability to slash tires with blade?
*GXT entry still exists for this stat.