Namine does not look like Kairi to me at all....same for Sora and the BHK. The BHK looks like Cloud in FF7 to me....in that one CGI/FMV scene of him with Aries or whatever....
Actually BHK does look like Sora, I mean they look SIMILAR. If you look at the magizine scan with the two of them, and that weird cartoon one (With BHK's face looking the other way, so you can't see it), they clearly arranged it so that they looked like eachother, they even messed up BHK's hair so it looked like Soras. They looked basically similar, but not exactly the same, same with Kairi and Namine (Don't mess with me about that line, or I will personally hunt you down!).
And play CoM again. She said shadow which meant Imitation. She was imitating Kairi in Sora's memories.
Meh... I don't know, they way Namine said it didn't seem like imitation, she said....
Namine: Sora will never forget Kairi... because I'm her shadow.
She did not mean imitation (I might have gotten it wrong, could someone get the direct quote?), look at the way it is worded. She meant in real life clearly, not in Sora's memories. It could mean that Namine has some connection to Kairi or something... If You can get it, it basically says the reason Sora won't forget kairi is because Namine is her Shadow. It could mean that Kairi is somehow connected with Namine in a way that Namine's life will always exist in Kairi's shadow, which is apparent in Sora's choice of memories at the end of the game... or something like that...