Morgan Scalley would probably be considered, but he would certainly not be a shoo-in. The AD would most likely want someone with a proven track-record as a D1 HC.

In 2015, Whit was pissed off at Chris Hill. Do you remember that? It coincided with the empty spot at BYU. Some people thought that Whit might leave the U for another program. At that point, the athletic department was trying to assuage Whittingham's anger, but they also reached out to a couple coaches- to gauge their interest- for the unlikely event that Whit bolted. I don't know who all of the coaches were, but I know that one of them was Dan Mullen- who was at Mississippi State. He had worked at Utah, under Urban. I do not know whether Mullen would have taken the job- but he indicated that he was definitely willing to talk- at that time. (He's at Florida now, which is a Top 5 gig, and would certainly never leave there now.) I believe that the AD would look at coaches like that.

I don't think Harlan really cares if the HC is a member of the Church.