Tidus and BHK don't look alike despite fanboy fantasies. That scene isn't about Tidus and there's no real way to prove they're the same person.
http://i11.photobucket.com/albums/a1...cen-X/Them.bmp
I was thinking about this scene and the scene where he meets up with Namine. I was thinking that their meet up could be her revealing to him that they are shadows of Sora and Kairi and the above scene could be him trying to figure it out. *cliffhanger*
About the third keyblade. I think the first was BHK's by the mention of that possibility of him being a past Keymaster. I think the second was King Mickey's which explains why he has one and knows so much about it. The third is significant because it will be used to open the door to the light. This is why Mickey and BHK try to find Sora. I think actually, all three keys will be necessary. *tangent*
I think that Sora's world is the world of darkness and BHK's world is the world of light despite Namine calling herself a shell/shadow, I believe this is how it'll play out.
Also, if the rest of Twilight Town's characters are shell/shadows of the Destiny Island kids, then there's still one person missing.
BHK = Sora, Namine = Kairi, Camo = Tidus, Chub = Wakka, Tanktop = Selphie, ? = Riku. I believe that despite the fact he's older, it's possible that Axel is BHK's rival as Riku is to Sora. I believe this to be the reason behind BHK's encounter with Axel; more accurately, I believe this is how he knows Axel is after Sora. Meh.