The decision making should be pretty easy at this point. The staff has to go. The only guy I'd actually consider bringing back is a guy like Al Harris, who I think did a nice job. McCarthy? Quinn? OL coach? Schottenheimer?
Good bye. And it should be done in the next few days. Not a week or two weeks from now like it typical for Jerry. It needs to be done now. Because if he wants a guy like Belichick*, then you go and try to get him now, not drag your feet for a week and then possibly screw up your chances of getting the guy you would want.
You don't touch Dak's contract. You hire your staff and then you let them decide if they can win with Dak. Then, only then, do you consider touching his contract. Jerry, likely, will do this backwards and foist Dak upon the new coach (or cause him to lose a coaching candidate who wants to start fresh at QB).
* As for Belichick, I really have no idea what I think of him. Is he just washed up like a Parcells was at the end or was he just stuck with churning a mediocre roster post the Brady run? I have no idea. What I'd really like is a great young offensive mind like a McDonald or LaFleur. Let a guy that knows offense then decide if he can work with Dak.