I realize you meant Compton (others might not) so just wanted to throw that out there. As for the 3 guys you mentioned, i like Jeff Allen the best. He's the guy i would target in the 3rd. I think he could play either G or T and shows good feet and is a solid run blocker. I do like Bergstrom, but like you mentioned i think he moves inside b/c he has short arms and isn't the most athletic guy so he would probably struggle against speed rushers. He could definitely start early on b/c he's experienced and older than most, having served his Mormon mission. I would target Bergstrom and Compton in the 4th.
Later in the draft i would take a serious look at Dustin Waldron from Portland State.