Rinne obviously is a no brainer but as you said, it will take A LOT to get him and maybe A LOT is still not enough. I know if i had him (I do in one league), he would/is borderline untouchable.
From your list, i honestly think the time to strike on Halak is NOW. You need to strike and try to land him before he takes the ball and runs with it.
St. Louis will have to send Allen back to the minors because Elliott would have to clear waivers and they won't want to risk losing him for nothing. They will try to reap some sort of compensation first. However, don't expect to see him playing much, so hopefully the Halak owner is not that keen or lacks the vision to see that and you can land him. I think you need to try and make that deal within the next week or else his value is only going to go up.
Halak has been ultra consistent the last few years. Yes he split time with Elliot last year but he is still consistent and Hitchcock still employs a good defensive system and they're a good young team. He just missed a couple weeks and comes back and gives up 1 goal in almost 65 minutes of hockey.
Rask i think will be easier to get than Rinne, but depending on who the owner is, you may have to give up a lot there too. But i would definitely kick some tires for sure
Price is a fantastic goaltender but i'm still not sold on Montreal as a team. I think they are playing a little over their heads right now.
you are right that Smith and Quick may be your best bet, because he has something to fall back on.
I would give up Skinner for Quick in a heartbeat. I would NOT give up Marchand. I think his offense and penalty potential makes him extremely valuable.
Skinner is a great player but is now going through his 3rd concussion in two years. He had 2 last year. I would move Turris or Saku Koivu too but i don't think Saku would interest him.
Quick will still probably be harder to get but LA still has more potential to consistently win than Phoenix does.
And also, don't discredit that Miller who has a history of turing things around will also reap the benefits of a new system and new coach.