I really believe he will be unhappy as a HC, because I think he loves the nitty gritty, and sometimes as HC, you don't have time for that. I could be wrong. I do know he is a motivated and talented DC.
I am surprised that OK did not go after TN's coach, since he played QB for a Natty there.
Heupal was an OC under Bob Stoops. It did not end well there...and I'm sure Stoops had a big say on who would be HC.