While I do think that the Leafs need to keep their core together, they have to give up a few pieces to either stay affordable or balance the team, hence the Sandin trade. They should see if any of their youth can play a part of their roster, instead of potentially overpaying for potential fits like Ritchie.
Thompson is a very valuable and cheap backup/1B, so I do see Vegas struggling to move him. However, with the state of their team, I think it could be a win-win move for both teams.
Bringing back Campbell is a risky move, and might even not happen, but I think that this is the perfect contract for what he brings to the table. As long as he has at least a .910 sv% and improves a bit on shots from the slot, I think that he would be the perfect candidate for this spot.
Obviously, the first line stays together, but the second line has a few question marks. You have to start Robertson there, because it is the only place in the lineup where he should be. Hopefully, he can help that line come out of the gates firing. Also, Nylander plays like he has been for Sweden, it most fans saying to trade him will be eating their words. 3rd line is a shutdown/checking line, and it is the same for the fourth. The only issue I have is Blackwell is 5'9", but he does play bigger than his size and digs in the corners, so he will be annoying to play against I guess. Nonetheless, this should be a good forward group that can check, score, and defend very well.
If they can get Boosh back anywhere less than $2M, I think they have to jump on that. He was a great fit, and he is a good option to have. Muzzin and Brodie are a very good shutdown pair, as long as they both stay healthy. Muzzin has a full NTC, so it sounds like he will be here next season. Lastly, Gio and Liljegrin worked out perfectly this season, and Liljegrin should be affordable if he signs a bridge-like deal.
As I already said, the goaltending should be both cheap and effective, which this tandem gives. it could be a 50/30 split, and if one gets hurt, we have Kallgren and Woll to step in.
When making trades, Dubas should be looking to get more picks and potential assets, as the Leafs do not have very many picks the next few years. These picks can later be flipped at the deadline if necessary.
With the way the division is shaped up next year, this is a team that is very capable of winning the Atlantic, and maybe even breaking the franchise point record yet again.
Kerfoot could be potential fit, if they either want to run it back once more or decide to flip him at the TDL. Duszak was a top AHL defenseman who requested a trade and does not have a spot on the Leafs, but could maybe find a role in Nashville.