The Isles are likely to go 8-1 and don't need to protect 4 forwards at all. The fact you waffle on forwards past Tavares/Lee/Ladd and claim several times that the Isles are likely to lose a strong defenseman is all the more reason to go 3-5-1 instead of 4-4-1.
Unless there's a trade to bring in a forward, Tavares, Lee, Ladd, Leddy, Hamonic, Boychuk, DeHaan, Pulock is the preferred list, ensuring our five best defenseman remain in the organization at the likely expense of Nelson or Strome, who Vegas will be happy to take considering the lack of young top-6 forwards that will be available. If they still want to take a defenseman from us, they can choose from Pelech, Mayfield, or Hickey.
But you're not that far off. I've seen lists where Hickey gets protected over Leddy, where Chris Gibson gets protected over Griess, so when my biggest complaint is protecting Nelson over DeHaan, (something I wouldn't put it past Snow to do) eh it's a decent read of the situation.