Sora
Zero Graviga
Salvation
Mega Flare
Shadowbreaker
Balloonga
Curaga
I had Sonic Blade and Ars Arcanum in there at various points throughout the game, but I didn't like how easy it was for them to miss their targets and just go swinging off in the opposite direction.
Riku
Zero Graviga
Mega Flare
Dark Splicer
Dark Aura
Curaga
Thinking about replacing Zero Graviga with Baloonga or something for Riku.
The only things you don't keep are the stat ones. You get to keep support abilities (red orbs), spirit abilities (purple orbs), attacks, and items once you unlock them.