The fact that you still have this core 3 locked down, and many other players have strict no movement clauses like a Jeff Carter, the roster can't be "blown up". Unless the players themselves are willing to be traded. For example, everyone knew that the marriage between Mike Sullivan and Phil Kessel had come to an end. The Pens worked out a trade with Minnesota (ironically for Jason Zucker) and Kessel vetoed the trade. For some reason he agreed to be traded to Arizona (warm weather) and the Pens lost a bargaining chip.
So in saying all of this, I doubt you can change many of the players. So you have to change the coach. This last week where they needed wins against the very worst teams and they lost both games, sounds like to me a team trying to get the coach fired. Not exactly laying it out on the line for him (or themselves).
Boston has been successful over a smiliar timeframe, lost in the 1st round last year after having 112 points and they fired him and brought in a new coach, Dan Bylsma won a cup. We fired him. We can't let 2016 and 2017 just dictate coaching terms.
But...
You don't re-sign Jarry and Dumoulin. That's two defensive liabilities out the door and new cash on hand.
There is a market for Petry if you want a salary dump with little to no return.
I'd say the same for Granlund, but they can always use centers, so I'd think he stays.
MP would have a strong market, and they wanted to trade him last off-season. He was solid this year. Do you sell high on him or keep and hope for similar results?
Guentzel is really a core player. Entering his contract year, do you re-up or sell high and bring back draft picks and young pieces? You have to give up something to get something.
Rust has a long but not insanely expensive contract. He disappointed this last year. With his performance and contract, you probably don't get what he's worth to the team back.
Do you try to trade CDS? A decent backup with decent metrics for a backup, but he's no 1A or 1B, and would anyone want him? I wouldn't.
Can you get Carter to retire? There are millions of reason why not. Buyout is the only option or you have to bring him back and hope that one more training camp and season makes him want to retire. Make him play 25-30 minutes a game in the preseason and hope his body breaks down to LTIR him.
A good new GM can overhaul the roster, but only a great one could work miracles with this roster.