It is incumbent on the employer(the AD Hathaway) to have a list of names in case the coach leaves, gets sick, or dies. Businesslawyer is correct here. This one isn't on Randy. I hate how he handled it but he has handled a lot of other things like Jazz Howard's death really really well.
Regarding P, he didn't undo all the things Randy did. He loosened certain things that Randy had a tight control over. He let the kids be more accountable but in the process, they lost the culture that Randy had created and that was the beginning of the end.