I'd say KH: COM (GBA version, since i didn't play Re:COM yet) because of the strategy added to the battle system. KH1 and KH2 (witch i didn't play entirely also) are more buttom-mashing, witch is fun, but takes out some of the strategy.
Quick answer:
at start of game, definitely Goofy.
at end of game, definitely Donald.
Elaborate answer:
If it's with their initial settings, Donald wouldn't stand a chance (little HP and MP, does not have Cure, only Fire).
If it's late in the game, with all powered-up characters, then it would be a lot more interesting. Donald could cast Stopga on Goofy and bash him until the effect goes out, then repeat, use Aeroga to raise defense AND cause damage, Cure himself, use Gravija to wipe out Goofy's HP... there are many more possibilities.
Ducktales would be great! I've totally forgotten about The Incredibles and Monsters Inc. They would also be pretty interesting (imagine Sora & co. turning into little monsters, or insects).
That's good... I don't know him, but according to what he said in this link you provided, his work in the game is already concluded. So, the other v-a's must be almost finished too, otherwise, it would not make it in December 2nd.
Does someone know, have any idea why it's presented this way in KH2 intro?
Something I missed? I haven't played the PS2 Re:COM yet (i'll buy the American version coming next December), so I don't know if there is something there to clarify this.
I have this little question about the Stop family of spells... when i Stop an enemy and strike him, his health bar doesn't go down. Why is that? Am I missing something?