I agree with your thinking.
Campbell is just such an insane target that I can't wrap my head around it happening (although I will be happy as anyone if it happens.)
Fickell and Fleck make the most sense to me - both are great coaches and program builders. Neither have any integrity issues in their past.
Specifically with Fickell, it had to have been made clear to him this year that a G5 team can't make the playoff in its current form. If you want to compete for it all, you have to move up. He was close to taking the Michigan State job last season so we know he wants to move if the situation is right.