Sora actually can use sleep magic he learns it in KH DDD by getting it from the Tama Sheep mirage board. As for self buffing... uh? Have you played KH1 because that's literally what Aero magic was in that game it was a defense and evade extender self buff. everything else I agree with though.
Sora would play pretty much nothing like DQ Hero, the magic that they use isn't even the same apart from like what? Fire? If you actually look at DQ Hero he looks like he borrows a **** ton from link for his basic sword combos pretty much every one of his attacks are Link's attacks. The only thing thats different about him compared to Link is his magic attacks that's about it. Sora's basic sword swings and magic attacks on the other hand would very likely look completely different from all the other characters in the game mainly due to the fact that we already know his sword combos do look completely different from the sword combos of Marth,Ike, and Link. And Sora has magic attacks that look nothing like anything we already have in the game, things like Reflect, stop magic, water magic, explosion, gravity magic, magnet magic, and even balloon magic. Along with his other more well know projectile elemental magic fire, thunder, and aero magic that would look/ function similarly to stuff other characters have.
All of that and I haven't even started talking about his air combo potential, Sora has very large aerial potential with what they could do for his aerial combos which in his own games are quite expansive and long and tend to end in fairly strong finishers. Which already be very different from pretty much every other character we currently have. Then there's Sora's more unique abilities like Sonic Blade, his glide ability, his drive forms, and his more recent ability of keyblade transformations. Which literally change how his keyblade looks and works. Which in and of themselves alone not even counting magic or his regular basic attack combos could be a kit in and of themselves.