Re: James Buchanan Barnes aka The Winter Solider
I'm still voting for Anton Yelchin, especially if Chris Evans is Cap.
It would just be too weird for Chris Evans and, say, Robert Buckley to be on the same screen together -- they've both got the same Abercrombie jock look and look about the same age, build, height etc.
Yelchin has played at least two "little brother" roles that I can think of. He was great in Terminator Salvation as the young counterpart. On Star Trek, he felt like the baby brother of the cast, too.