there is no comparison of your coaching prestige to his, or whatever, as far as i know. it is a far simpler mechanism and i'm not sure its a mechanism that totally makes sense either. but basically when a coach FIRST joins a school, and only then, sometimes the prestige of the school is bumped up or down 1 partial grade, maybe based on that coaches success compared to the prestige, but maybe based on other junk like loyalty, who knows. nobody knows how this affects prestige going forward in d1 either, i believe.
anyway just saying, i don't think the resume of the previous coach has anything to do with it. but i think if someone had watched the time, you'd know for sure. the prestige change for the new coach is instantaneous, and the draft prestige change always happens at the same time, so if someone was watching that timing, i think they'd know for sure? not sure how you could tell in retrospect though which it was.
also i think someone said the EE boost only happens if they were your EEs. i think there are 2 things there. first off, there is the prestige change for the school. i'm not sure about that one, that might happen regardless, and i kind of think it does. meaning i think a school gets the prestige bump from draft picks no matter who the coach is and whether that coach recruited the guys originally or what. but there is also a coaching resume aspect of draft picks, and that one is almost definitely dependent on the original coach being around when the player is drafted. most of the resume is based on the last 10 seasons, plus loyalty/reputation - but there is also a permanent effect from championships and draft picks, or something like that.