I think the others have made it quite well known their gripes with this, so I will attempt to take a more constructive approach.
I will start with what I like:
I think you got the aav for Kapanen and Johnsson pretty much bang on. The only thing I would change is that for that aav, Kapanen gets 3 years. The rule (for both Kappy and Johnsson) would be as follows: 1-1.99 million = 2 years, 2-2.99 million = 3 years, 3-3.5 million = 4 years.
Just a tip when using the site, when you are trying to put a player on LTIR, instead of trading them, move them to the LTIR slot. It is in the 3rd blue bar, just below the goalies when you are building the ACGM.
On to the other things:
I think you are off on some of the contracts here, by a decent amount too.
Matthews needs to win at least 2 trophies to get that aav, and minimum 1 to get 12. He will likely get something like 8 years @ 11aav.
Marner I cannot see going over 8 years @ 8aav. He is a damn good player, but woth his comparables and his production, that is roughly his max.
Never give your backup goalie that much term and that much aav, it is a recipe for disaster. Sparks will get about 800k on a one or two year contract.
As much as it pains me, I don't think Leivo is coming back, and even if he is, it won't be for that much. It will likely be just under 1 million, or somewhere around there.
Ozhiganov and Lindholm have played well since coming over, and I hope we resign them. I think they get matching contracts: 2 years @ 1.5 aav, or somewhere around there.
If Rosen makes this team next year, it will be as an extra, and he will accept his qualifying offer, as no one will offer anything else. While I do not know for sure what that would be, CapFriendly says his salary will be 0.925 aav should that happen.
If we are bringing back Marincin, it will be as an extra, so only ever 1 year for the term.
Ennis will not be back. Either he doesn't work out, and we don't want him, or he does and we cannot afford him. We have better guys on the Marlies anyway.
Edit: I will link some ACGM cap charts to help you with the big 3:
https://www.capfriendly.com/armchair-gm/team/877874
https://www.capfriendly.com/armchair-gm/team/884206 <-- Just a warning, this one is incomplete, but still has valuable information.
On the trades:
Gardiner will likely get the same treatment as JVR and Bozak did last year. He will play out the end of his contract as we try to make a run, and will likely leave as a UFA. I think that if Dubas somehow makes it work, they want to re-sign him. I also think that you do not know who the prospect you traded him for is (he is good).
On the Nylander trade, there are three big things. The first is that Ristolinen is a similar player to Jake Gardiner. If we wanted that, we would just keep Jake.
The 2nd thing is that Nylander is worth much more than Risto, so you would be selling yourself short. This trade would look like Hall for Larsson very quickly.
The third thing is that Buffalo, like Toronto, needs Dmen, and won't trade one of their more experienced ones. When making trades, you have to factor in what the receiving team needs as well.