Jeremy Pruitt is a bad choice for UToothless for the same reasons that Muschamp was a bad choice for Florida: he is a longtime defensive coordinator and first-time head coach trying to rebuild a program where he is a complete outsider.
Chip Kelly is a bad choice for any school other than Oregon, because his college offense formula only works in Oregon with a bunch of assistant coaches who also came up through Oregon. Kelly does have the advantage of college and NFL coaching experience to guide him through tough times, but he needs to adapt to changes in college football--most notably the increase in the number of other teams using spread, spread-option, and RPO plays that make his playbook look more familiar to modern defenses.
Scott Frost is a good choice for Nebraska, because he was a fake national championship QB at Nebraska and has legacy there. His rebuild program will be difficult, because Nebraska is no longer in the Big 12, no longer has a monopoly on strong linemen in the Midwest, and no longer has a secret inroad to Florida talent. He is going to learn quickly that his short time at UCF was a fluke, and he only has that year as head coach to draw learning experiences from.
Dan Mullen is a good choice for Florida, because he was an assistant here for two national championship teams. The recruiting landscape is not much different now compared to a decade ago, other than the fact that more teams from outside the state are poaching our recruits. He has a decade of head coaching experience in the SEC, so his only adjustments should be in figuring out how to recruit head-to-head against a much more powerful Alabama and Georgia, as well as a more difficult competition from the other 120+ teams recruiting the state while UF has been down.