^Well, if it helps any, I've read enough of your posts to know that you're definitely not racist or prejudiced in any way.
I didn't find Evans and Alba convincing as siblings either, in the same way that I didn't find Sean Connery, Dustin Hoffman and Matthew Broderick convincing as grandfather, father and (grand)son.
Whenever we watch the original 1941 version of The Wolf Man,
my girlfriend always snickers at the idea that Claude Rains (small, delicate, and British) is supposed to be the father of Lon Chaney Jr. (big, burly, and American).
Granted, they throw in a line of dialogue about how Lon was educated in America . . . .