I would hope they learn from their mistakes. You trade any UFA to be if you are out of contention, which in all likelihood they will be. Metro is a tough, tough division.
There is a lot of solid youth on the way but Lee is the only one I would definitely resign. He's a monster in front of the net and he's improved every year. He is good for one bad offensive or defensive stretch every year but he's going to pot goals, going to keep a defense honest (and really busy trying to move him) and is one of the only forwards on the team (with talent) that can stay in the dirty areas and be a threat.
Eberle looked great with Barzal but there are enough speedy wingers that are cost-controlled on the way up and Bailey is a lock to play top 6. If Eberle has another season like the one he just had and the cap continues to increase, 7m + on a long-term is not out of the question (but it should be for the Islanders).