how does Vin Diesel's prefer to be ethnically classified
Everything I've seen suggests that he doesn't.
why interracial people so pretty
Well, they are less inbred than everyone else. Facial features resulting from infrequent gene combinations can turn out to be very striking. Supermodels can, in comparison, look downright boring.
many celebrities identified as white have non white ancestry
Everyone identified as white has non-white ancestry! Why would celebrities be exempt?