I promised a guy a guaranteed start and 15 minutes per game.  He's gotten what I promised, but I'm wondering if he still requires both of those things as a sophomore/junior/senior to be happy. I recruited another C who I actually used FSS for, and he's just exploded in ATH,SPD,REB and SB so that he's know ahead of the starter in most categories, and has a higher IQ.

Nope, the promises only apply to his first year with the team. If he plays sparingly he's likely to complain, but as long as he's a regular member of the rotation, you should be fine.

Along these same lines, I recruited a senior transfer as a placeholder until my non-qualifier was available next season.  I guaranteed him a starting spot and then decided not to honor that as I wanted to develop the fresman I brought in at the same position.  Will my reputation take a hit for not even trying to get the senior the starts he was promised? 

Yes.