I think #4 is on the right track, if a bit better polished, I think the concept is good. I don't like his shirt, or perhaps where the shirt is cropped. People will be bothered by the right side crop, but I think it adds to the sense of informality, which I like.
Out of the group, I think #4 is the only one, maybe #5 with some color work. #2 may have worked with more DOF?