As far as Kubalik, CHI will tender an offer, (especially since its so cheap), so even if he does find his way to TOR, it wont be free.

And your signings/re-signings are pretty good, but I just dont see a team better than 21-22. Its basically the same team, with some of the same issues:

Age: In 21-22 Toronto was the 10th oldest team in the league, in the playoffs/end of season they got older with clifford/giordano. Still have dependency on Spezza, Muzzin, Simmonds, Clifford.
Unreliable commodities: Kase surpassed expectations last season by actually playing more than a few dozen games, but hes a concern every game. The bottom 6 dont have tons of firepower. Kallgren is not a good backup (3.31 GAA and .888 save %). Very unlikely that robertson/abrueze/kubalik replace Kerfoot/Spezza/Mikheyev in production or two way play.

Im not calling for an overhaul, but this is really the 21-22 team without Mikheyev, Kerfoot, Holl with really just the addition of Kubalik and (hopefully) the arrival of Robertson/Abrueuze.

This season's team was a coin flip away from the eastern conference final. I would say running it back is a wise plan. I think Mikheyev is likely gone but his 2 empty net goals and nothing else in 7 games may hurt his contract a bit so maybe he is still affordable. I think Kase is likely gone. His health is is just too unpredictable and I think you can find a better 4th liner who hits or kills penalties.

Calling the team old is rich though. All the heavy lifters, beyond JT (who is still a great player) are under 30. I guess you can say Brodie is pretty major as well. Simmonds, Spezza and Gio lift the average but have proven to be capable in their roles still.

CHI will probably offer Kubalik a contract but it most likely won't be a qualifying offer. So it's up to him if he wants to take a prove it deal with CHI or see how free agency plays out.