Yeah, they already fired the only non Rex guy on the staff, nobody really left to have the Interim coach label. Dennis Thurman is basically Rex Ryan's puppet. Anthony Lynn is a Rex guy as well as most of the staff, You certainly aren't promoting his brother. He signed a 5 year deal, I know that doesn't matter but they likely aren't going to walk away from that and pay 20M in dead money. Also forgot about Dareus in rehab, which isn't the coaching staff's fault.
You could see Whaley gone in the offseason and then see if they want to keep Rex, I feel as if Mr. Pegula will add a football czar to the staff which he has wanted to help Whaley.