I really cant see the Isles dealing Beauvillier unless he is seeking a contract that he Isles aren't comfortable with. His qualifying offer should be a hair over 2.1M. He has arbitration rights. If it gets that far, who knows what an arbiter would decide. Somewhere in the 4M range perhaps.
Isles have been so close to the Cup Finals the last two years. I would be wanting to add pieces to my NHL roster, not swapping them around. Getting Anders Lee back next year will be a huge boost. Putting all that together, maybe the Blues retain 2.5M and take back some combination of Komarov, Hickey or Panik. In return, Isles send futures to the Blues. Sorokin, Wahlstrom and Dobson are closest to NHL ready. Kiefer Bellows, Samuel Bolduc and Bode Wilde would probably be in the next grouping with 2021 selection Aatu Raty on their heels.
I'd prefer a hockey trade for Tarasenko but I'm not sure one exists. Throw some conditional picks in the trade and add 1 or 2 prospects, retain some salary and take back a contract and call it a day.
Tarasenko (2.5M retained)
to Islanders for:
LD Thomas Hickey (1 year at 2.5M)
*2022 Conditional 2nd Round Pick
1 of Kiefer Bellows or Aatu Raty
1 of Dobson, Wilde or Bolduc
2022 Conditional 2nd Round Pick becomes a first rounder if Tarasenko scores 20 goals or the Islanders make the cup finals.