I really can't address the DBs with any real background, but I also coach (D-line) at the high school level (going on my 6th year). I'm not a paid full-time coach, it's something I do to help the school and because I have fun doing it, so I am by no means an "expert". It's not uncommon at all for a lineman to add 40+ pounds from the end of their junior year to the end of their college career. As you probably know, the biggest kids end up having to lose weight...regain muscle...before they ever even see the field at the collegiate level.
As for JKM, I just don't get the feeling that he's trying to do anything more than have a discussion. JKM certainly understands the game far more than the average fan, but I don't take his posts as "I'm right and all others are wrong". Plus, he's been around (as have you) long enough to know he isn't like that.
Eh, I'm kinda done with this one. We probably spent far too little time discussing the actual commit in this thread...but, that's what we do!