Something I didn't get was.... (Spoiler)

[Benihime]

its most likely KH3 Riku due to Xehanort appearing at RG when Ansem the Wise found him.

if it is, i will laugh

riku got a freakin' differnt body while sora gets the same one from KH2(trailer ending)

EDIT: HE EVEN GOT A F***ING PONYTAIL!!!!

 

[Xehanort]

You'll notice that MX uses his Keyblade to unlock his heart. Years later when he has control over Riku and creates the Dark Keyblade, it also unlocks hearts.