Here is what I highly think.

Roxas-alike: Sora's older brother.
Female Knight: Riku's older sister (who else that has the same hair AND eyes colour).
Bald evil guy: He's already a Heartless (He's wearing the same clothes as Xehanort's Heartless wearing)
Eye changing colour dude: He's Xehanort before Ansem found him (I got nothing that says otherwise).
Baldies' Heachmen (same one that apear next to the bald evil guy): Did everyone forget about him/her? (Wearing the same getups as Riku was wearing in KH1 when he's using the dark Keyblade, - the mask/helmet).
Mickey: How old Mickey real is? (As in also is the SAME Mickey as in Timeless River?)