I was thinking about this today. What would be the best way for Kirk to retire and make sure his hand picked successor takes over?
He may need to take a page from Bob Stoops retirement guide and retire in June. I am guessing June 2020. By then it would be too late to search for an external candidate, so they will have to promote from within.
Which probably means Iowa would make Brian the interim coach, after Brian gets off to a 6-0 start, then they will make him the permanent coach and Iowa will finish at 7-5.