Assuming the Islanders ink JT
They have to work on an extension with Eberle as soon as allowed. Offer him the same deal Bailey just signed, If he takes the contract (roughly 1m cut in cap), you can then offer Lee the same contract (roughly 1.5m raise) and both contracts become cost neutral. Then you can hold onto both until either Bellows or Ho-Sang push their way into the top 6, or cap becomes a problem (Barzal/Beauvillier needs raises). At THAT point, you look to trade one or both of Eberle/Lee. When they are still signed for a handful of years to manageable deals, you've got their replacement(s) AND JT locked in.
They can sign both Eberle and Lee to the Bailey contract, and retain everyone they need including Tavares. It shouldn't start hurting cap space for another 2 years when Barzal comes off his ELC.