General:

DK's tipper jab combos into grab and utilt.
Zard's jab can be mixed up into dtilt or grab for damage and usmash or fly for kills. They may be guaranteed at higher percents. DK should jump airdodge or run away to escape them
Zard is faster in run speed, but DK has a better walk with faster walk acceleration. Zard has better options out of dash.
Zard has an amazing bair to space with. It hits very hard, goes very far, and has a bunch of disjoint.
DK has an amazing bair to space with too. It lasts 10 frames and can be done twice in a shorthop, but it doesn't have disjoint except a bit at the tip.

Charizard's specials other than Flamethrower are risky but powerful.
Flare blitz is extremely risky, since DK can punish it with a punch. DK should jump over it or shield it and punish, but he shouldn't shield it if his shield is low. If Zard hits a shield, DK can lock, use a punch, or chase the getup and grab. It does 10%, so it could possibly be useful to get out of ding dong percents.
Rock smash starts late and has a lot of ending lag, but it gives him armor starting at frame 5. It can be used to power through a juggle or attack and hit the opponent back.
Fly starts pretty fast and has frame 4 armor, and it kills. Its initial hitbox is just in front of and a little under him, so Zard can pick up opponents and kill if he lands on them. Utilt beats it. Zard can also do it out of shield in case DK misspaces an attack. Sometimes fly fails for some reason, and we don't really know why.

Zard's head hurtbox is stupid, so DK should aim for it. His tail only has a hurtbox at the base.


Neutral:

In neutral, they should try to wall each other out.
DK's goal will be to get grabs, as he only gets good damage output from grabs and juggles.
Zard wants to space DK out. His zone is a little bigger than DK's because of his higher dash speed. Maybe his spacing should be so his tilts/jabs will hit DK's tilts' extended hurtboxes, though throwing out tilts is a bad idea because DK can bait a whiff and grab.
DK's spacing options are jab1, dtilt, and sh double bair. Jab1 can lead into followups and is relatively safe. Dtilt has followups and is relatively safe but leaves a hurtbox extended after it ends. Bair extends a hurtbox but is safe on shield and can be done out of dash.
Zard's spacing options are jab, dtilt, and fair/nair/bair. Jab loses to aerial approaches. Dtilt isn't vulnerable to aerials but loses to hitboxes that are already there. Aerials are more committal, so they can be punished out of dash if they're baited.
DK's offensive options are dash attack, dash grab, and bair. Dash attack loses to shield and dash grab loses to attacks. Bair loses to spaced attacks but is safe on shield.
Zard's offensive options are dash attack, dash grab, fair, bair, and flamethrower. Dash attack loses to shield and dash grab loses to attacks. Fair and bair are good against shield but bair is vulnerable to spotdodges. Flamethrower is a zoning tool that's safe on shield and generally on whiff. DK may be able to jump over it, but Zard can angle it up and catch him.



Zard advantage:

Zard can platform pressure with utilt, bair, flamethrower, or rock smash. He must be careful never to get grabbed on a platform, though; his head can also be grabbed through the platform if he's not careful, if most of his neck is through the platform. Ding dong kills early on a platform.

DK should DI dthrow up and out. Zard can dthrow > usmash/fair/nair. After nair he can try to set up for a regrab, so DK should jump out. DK should always jump out anyway, especially at the ledge.
Zard has jab mixups, and DK should either jump out, up-b out, or airdodge out. Zard can use usmash or fly to kill after jabs, and he can mix up into a tilt or shield to rack damage. (Test how good jab mixups are on him)

Usmash and utilt juggle DK, and both are intangible. DK has high air speed but kind of low air acceleration, so after a juggle he can't get away too easily. DK's landing options are b-reverse punch and ac nair.

Flamethrower, dair, and dsmash edgeguard DK hard. After flames, Zard might
be able to hit with dair or dsmash. Zard should get rid of DK's jumps first because they go very high. Ftilt angled down can hit him before the 2-frame because his regrab range is bad?
DK should mash up-b in case flames hit him, or he might not react fast enough to hit it again.

Nair can cover all options at the ledge unless DK waits a bit. DK also doesn't have much of an option against ledgeguarding if Zard spaces himself well.

Uthrow kills decently with platforms, maybe at 120 without rage on BF's highest platform. DK should DI it down and away.




DK advantage:

DK can platform pressure with uair, side-b, and the threat of a grab. At low percents, if he uses nair and Zard slides off the platform, DK can lock with dtilt for big damage.

Cargo uthrow combos can do a lot, so DI out. At 0 he can only do CUT > uair/bair, he can do CUT > bair > bair at some percents, he can do CUT > fair at mid percents. Airdodging is a bad idea, especially because you might get regrabbed on a platform.
Ding dong % is 77-90 without rage. It's also a 50/50 until 103%? Stops working with like 100% rage.

DK juggles Zard with utilt and uair, which are both intangible. Zard can make
utilt a 50/50 with rock smash and maybe land nair through it. During uair, DK
can position himself so he doesn't get hit by rock smash afterward. DK can sh
ff ac uair to juggle better. Zard can land with fly too, and if the opponent doesn't block it can kill; utilt's hitboxes outrange it though.
    Utilt reaches far so Zard might have to start it early.
Zard's landing options are rock smash, flamethrower, b-reverse flamethrower, bair, ac nair, and maybe fly.

DK can do a Melee Puff wall of pain with bair at like 40-60, where he strings 2-3 bairs offstage and makes it back. Charizard might be able to recover from it if DK doesn't commit enough.




Stages:

Both characters like BF and TC for the same reasons, that they can juggle/land
more easily. DL is in Zard's favor because it makes flamethrower off the ledge
better.
TC makes juggles irrelevant. I don't know who benefits from this more.
Lylat might be the best stage for DK because it limits Zard's autocancels and DK can shark with utilts.
FD makes it an even field, so Zard probably wins because he's better in neutral.
DH gives Zard more active frames on bair and makes his ftilt all sweetspots, so he's significantly stronger there.