McCaffrey, Cook, and Henry are 1, 2, and 3 in terms of yards from scrimmage, so I expect them to all be in that top echelon of $. Those three have proven they can take the #1 load at RB, and be good to great in the passing game to. Henry not so much as McCaffrey and Cook in the passing game. Kamara is different to me. Not sure he can take a #1 load at RB and be near as effective. He has far greater reliance on a complimentary every down back.
While I'd be happy to pay McCaffrey and Cook franchise type dollars, I'd have reservations about Henry and Kamara. Purely my opinion, but I could see Henry burning out quickly, and Kamara taking a big production drop without Brees or other elements. Like we've seen several times in the recent past, a lot of teams get burnt on big and long term RB contracts. It's simply a position, right or wrong, that is devalued and doesn't have a long life span.