Here's my theory: Terra, Aqua, and Ven are apprentices of an unknown guy and were ordered to destroy that...dude..with the bald head (forget his name already, oy x_x) and...so yeah. Since the story will take place ten years earlier...well...that would make Sora...5 years old. O.O maybe one of them gives Sora a keyblade or something..............i don't know. my theories suck. and yeah, i can't wait for the game to come out. i wish it was coming out for PS2 though...but i have a PSP so no worries.
I'm just wondering if she's Kairi's heartless since namine is Kairi's nobody, and we never found out who her heartless was. but i did read that ansem said that when kairi lost her heart, a heartless wasn't made...so...there goes most of our theories (or at least mine)