I don't know if they will resign either Sheahan or brassard. I think blueger(or some other AHL player) can come in and play 4c or they can sign a player like grant for close to league minimum for it if nobody from ahl steps up. For 3c I do not think Sheahan is the best fit and brassard might price himself out. So they might have to look for a free agent somewhere between the two of them.
For 2million I would definitely want hagelin back but idk if he will get an offer for more elsewhere or not.

Hagelin will most likely get the exact same contract from someone else, he literally is the exact same players as when he go the 4 M contract, hasn't lost a step, still scores the roughly the same amount, CAP going up...I would be extremely surprised at anything less than 4M.

No way to keep Brassard and Sheahan. It makes no sense to me, cause, as Awesome said, Blueger can be the 4th line C next season. I'm with him also that Brassard should get more than that in FA. So, he's right when he says that Pens better option is to sign someone else in FA.

As for Hagelin, this season will determine how much he can get as a FA. It'd be nice to keep him for something about 2M. But it's possible to see him getting more than that. Take a look at Beagle's contract, for example.