I will still be surprised if he is fired before 1 January with a million dollars at stake.
Also, if they are looking at Harbaugh, his regular season does not end until 28 December and they are still in the playoff hunt.
Further still - and this is pure conjecture - since it is a public university there may be formal rules that must be followed in order to make a selection (such as announcing the position and holding it open for a defined period).
All that said, I am sure heavy duty work behind the scenes has been going on for some time. Locking down the right guy is paramount. Making it official quickly is not.
As for the players (assuming there is no bowl game and that damn well better be the case), nothing will be going on but winter conditioning until Spring practice, and I believe the coaches involvement in that is restricted by the NCAA (not that UM hasn't gotten in trouble for that before).