One thing that is probably underappreciated in the context of the moves Shero has made is that we'll be setup very well for the expansion draft. Realistically, assuming neither Greene or Vatanen is resigned during the season it's likely the only exposed players of any importance will be one of (1) Coleman, Wood, Zacha and (2) Schneider. Vatanen and Greene would be technically exposed but I would find it unlikely that Seattle would look to sign them in advance of the formal expansion draft.
The Seattle expansion draft isn't until the summer of 2021, so Vatanen will either be long gone or extended by that time.
Zajac, Coleman and Palmieri are all potential UFA's heading into that summer, which could provide Shero with some flexibility if they remained unsigned (could certainly see that being the case for Zajac, as I can't imagine him playing anywhere else). You also have one year left on a 35 year old Schneider at that point, so he's the easy choice to leave exposed at G.
With the Devils' depth at forward, would have to assume they go 7-3-1 instead of 4-4-1 this time.
A lot will change in the next two years, but right now here's my best guess of who gets protected:
1. Nico
2. Zacha
3. Bratt
4. Hall (or replacement UFA/player acquired in trade)
5. Palmieri (assuming he's extended ahead of time)
6. Coleman (assuming he's extended ahead of time)
7. Wood
Exposed: Anderson, McLeod, Bastian, UFA Zajac
McLeod, Anderson or Bastian could all work their way up to the protected group over the next two seasons, plus trades could impact the list as well. I don't see Zacha being exposed though.
1. Severson
2. Butcher
3. Subban
Defense gets more tricky with the Subban addition, as if Vantanen is resigned or the Devils acquire another top 4 defenseman, someone good will have to be exposed or NJ will have to work out a side deal to not take one of them. Perhaps the Devils expose Subban and his 1 year $9MM cap hit if he doesn't fully bounce back.
Blackwood is the easy decision to protect at goalie.