The person who made this thread is a retard. Honestly... Everything that comes out of your mouth (Metaphoricly) is comeplete crap.
Namine Being Kairi's shell: Absolutely impossible considering that Meleficent had kairi's body the whole time, while her heart was in Sora's heart! Like everyone else has said, Namine's Kairi's shadow...
BHK is Sora's shell: Hogwash. If BHK is sora's shell, why does he have a body? Kairi got sora back from being a heartless when she hugged him.
"There's only one keyblade": Seriosuly... Where do you get this crap? "Sora dropped his keyblade, so BHK picked it upo and started using it"... WTF? There are multiple keyblades.
One thing that completely annhilates your theory is that Sora's keyblade has a silver key, gold handle and a blue band in the middle. Now, in the Jump Festa trailor, you see BHK attack Diz with his own keyblade. Freeze frame. Now look at the keyblade... Silver key, gold handle, and a RED band in the middle. See? THEY'RE TWO SEPERATE KEYBLADES!
And then, mickey has his very own keyblade with a gold key, silver handle, and a red band in the middle. If the pattern follows, then I beleive there should be a Keyblade out there similar to Mickey's, except with a blue band in the middle...
BTW, Riku's keyblade was born of the six captive princesses hearts. Just thought I'd clear that up.
Try harder next time...