Don't forget one thing. I don't think Bronco will give guys like Havili, Kavienga, and Stevens another chance post-mission should they serve. He already recruited them, I doubt he'll do it again.
The reason why we hear about these other guys like Bradley, Sorensen, Nelson and Malosi Te'o is becuase we didn't recruit them or at least didn't offer them before their missions. They didn't turn us down already like the others.
Bronco is a proud man and he believes the opportunity to play for BYU should sell itself to every LDS kid. If someone passes up on that opportunity for a chance to play on a "bigger" stage he won't give them a second chance. He could find ten other guys who are nearly as talented and twice as dedicated. No one of these guys will make or break the team.
I thought it was interesting to see Sione Fua come to visit BYU's practice and talk with the coaches before going into the MTC. This is total conjecture, but based on the outcome, if he was indeed looking into the possibility of transfering (why else would he have come to a BYU practice and want to meet with the coaches?) I wouldn't doubt that Bronco told him, "Have a good mission, and enjoy the rest of your career at Stanford".
I have no problem with the way Fua went about his recruitment, unlike some of the other guys who strung BYU along to the last minute when they clearly had no intention of signing with BYU. He was very up front about everything and his desire to get the best education possible first and foremost. He decided on Stanford for just that reason. But Bronco recruited him once and he made another choice, honorable as it may have been. I have to wonder if the fact that he's back at Stanford now might be an indicator that it played out something like that.