Can you just trade away Salary you retained on a player??

no

2 1st, I know a lot of ACGM's want to get Chychrun, but i am not sure it is very the best option for the Sens.

Looks good in the short term, but they do have both JDB and Thompson RD that are looking to take big steps in the next 2 seasons, as well as Brannstrom that can play RD.

So after giving up 2 1st, and prospects for him you are only really getting 2-3 seasons of him, because if Sens can extend Stuzle and Debrincat the next off-season then there is no room to extend him unless you move a larger piece like Chabot. I know Zaistev can get moved, and Giroux would be done the same season, but that money will be needed for goalies, bottom 6 players, and other prospects as well.

In the end, I am just very unsure that moving a lot of pieces and 1st for 2-3 seasons of Chychrun, even including a potential return in flipping him his contract year, when the Sens have two great RD players in the system is the best asset management option for the Sens.

One would be given to dump zaitsevs contract. I’m not sure Jbd or Lassi are ready to jump into a top 4 role this year if we’re expecting to contend, and i don’t want hammonic in that role either. Other than severson, chychurun is the best option at the best cap hit. i like church run because he contract works out perfectly so that he could fill that top pair role until lassi or jbd are ready to play 22+ minutes with chabot each night. I wouldn’t mind just dumping zaitsev, but bringing in chychrun is what would push the sens into a playoff spots and take away many concerns that would come around lassi and jed’s transition into the league

How about bringing in PK Subban on a one-year 1 - 1.5 Deal? He will be hungry to prove himself again.

I hear you on the D, however, I also don't think Sens need to be in a rush to compete this year, really until Forsberg, Talbot or another option really show true #1 Starter numbers.
As is they would be on the bubble for a playoff spot I think, and really taking one more year before making any move that gives up a lot of assets and pushing the team to contend in the playoffs would be fine with me.