If ヴァンパイア are supposed to be pale...

Then the vampre has to suck even harder so they will drink there skin color out of them

The book says all ヴァンパイア get pale... It says that when Jasper is telling the story of how he got turned. He says the woman who bit him had Asian features but pale skin anyways... But they added an African American in the movie so I have no idea!
I'm guessing if one was bitten they'd remain with the same skin colour in the movie but become pale no matter what in the books.

I think they become pale because they lose all their blood.

Blacks idk what they look like when they look blood.

あなた ever seen a corpse on CSI? (Probably not) well the darker skinned people look slightly もっと見る ashen but still retain their general complextion, like Laurent as your friend said.