General Fanager has a pretty good mock expansion tool if you have the patience to go through every team to figure out their protectees, then draft the leftovers for Las Vegas.
Of course rosters will change a lot between now and the expansion draft. Can't see many UFAs getting a NMC this off season.
http://www.generalfanager.com/teams/expansion
For the Jets, I would protect:
F: Wheeler, Little, Scheifele, Lowry
D: Byfuglien, Engstrom, Myers, Trouba
G: Hellebuyck
Likely lose one of Burmi, Copp, Dano, Armia.
If one of those guys has a breakout season next year, could swap one of them for Lowry.