If Harvin goes on the open market he'll wind up with a 4 or 5 year deal for less than the average he makes now, probably substantially so, but he'll also get a quarter to a third of that guaranteed, which is more money than he is going to see next season. It's a completely open situation at this point. The Jets have the leverage if they're willing to pay for it and Harvin has all the leverage if they're not willing.
Probably true but he's also not a WR by trade. He's a playmaker and Belichik might well get drawn in by the same allure that the Seahawks and Jets did. Percy Harvin with the ball in his hands is almost never a bad idea for his team at any given point.