With Kingdom Hearts 3 coming out in January, I think that Sora coming to DHBM would make for the ultimate marketing move.
White skill: Firaga. Sora launches a massive fireball from his Keyblade.
Green skill: Aeroga. Sora creates wind shields around himself and his teammates.
Blue skill: Thundaga. Sora unleashes a lightning storm that damages and temporarily stuns all enemies.
Purple: Curaga. Once Sora is defeated, he casts a spell on himself and his team that heals his whole team, and even revives defeated teammembers. This skill can only be used once a battle.
Friendships: Mickey at 70, Violet at 59.
Also, give Mickey his Keyblade master outfit.