Edmonton would be upgrading Smith to Price, right?
If Montreal is eating 50% they will likely ask for a first round draft pick which could be in 2023 or 2024. Montreal wouldn't need it immediately which gives Edmonton some opportunity to move other picks for other assets.
Edmonton has a lot of forwards hitting RFA but Puljujärvi is the only one that's gonna maybe cost them. Does Edmonton want out of the Ceci deal? Cap dumping him to Montreal would free up some space to add Price no problem but would also cost the Oilers more in the return. Maybe Edmonton asks for Kulak in the deal as well to get a UFA defenceman with some versatility.
So you got Price at 50% retained and Kulak
Going back is Smith, Ceci and a package involving picks and prospects that Montreal wants for the return. Lavoie for sure, Broberg or Bourgault in the Montreal package plus a first in 2023.
So Edmonton loses a bunch of their prospect depth but also frees up the Ceci contract, Smith next season, gets Kulak as a rental, and gets Price at an affordable price for the next couple years of playoff runs.
Montreal eats $5M a year but can afford it in a long term rebuild with Weber on LTIR. Ceci can be traded or can just help the Canadiens suck as they eventually move Petry as well and run Ceci and Savard on the right side blowing games for them. But they'd have a couple French Canadian prospects in the bag and a first round pick down the road to look forward to. Smith probably gets moved in the summer as a backup to a contender who can afford him being hurt.
None of this happens until Price returns and shows he can still play, but that's the only way I see this working. Montreal giving up a lot, eating some contracts in return, and Edmonton dumping a bunch of A/B prospects and a later first. Of course this being Hockey's Future I'm sure the idea of losing any prospects for Price is considered heresy but that's how I see this going.