Maybe, just depends if Vegas would want Johnny or even Stephenson on shorter than the more expensive Hanifan.. Of course, all three have the option as UFAs too.

Hanifin resigned

Vegas has only about 2 mil in cap space. They are screwed beyond Marchessault. They are like to have to move either Karlsson or Barbashev just to be able to ice a team.

Send McNabb back to LA for a 3rd. Gives you 2.85m more to try and keep Marchy or Chandler.

That's not quite the math. Sure McNabb makes 2.8m but then you have to find a competent replacement for him. Even at a 1m replacement, the McNabb saving would be 1.85m
I didn't like the Hertl trade. Time will tell if that cap and his play will age well.