That'll only work if Kadri becomes the odd man out when you resign M n' M.

why would kadri be the odd man out? cap increases to 83M, plus gards, hainsey and hopefully par lindholm gone, gives us plenty of space to sign matthews and marner. were good.

this only works when you add to the trade because Dallas isn't going to cough up Faksa for 2 inferior players. He might not be putting up 20 goals, but at 24, he's fast and on a really low contract and he's a solid player that isn't getting his points due to the supporting cast around him. You aren't going to get that pawning off cast offs. You will have to give Dallas something they want.
Furthermore, you really don't want to waste him on the 4th line getting 8 minutes a night if you did manage to get him. With more talent around him to take advantage of his speed he probably puts up much better numbers give the ice time.
Considering he's one of the most sought after players on these boards from Dallas you should start thinking about adding a 1st and then hoping no one makes a better offer because your first round pick is going to be low round. Not that Dallas would even trade him unless the offer was really good.

Losing Gardiner might save you 2-3 million(for his replacement would be half his cost), losing Hainsey saves you 2 million (a rookie will take his spot for under 1 million) and losing Lindholm saves you 1/2 million dollars. So you saved 5 million $ now how are you going to make up the other 10 million to give M n' M their raises? And yes I know the cap will go up by 4-5 million and the Leafs are currently 6-7 million under the cap this season. But REAL NHL GM's do not spend ever $ of the cap before the season starts, so realisticly the Leafs cap budget for next season will probably be 80 million, so the team has a couple extra million to play around with and prepare for Dermott's and other players raises for 20-21 season. Plan for the future. And as pharrow states if you bring in a player like Kaksa who has 3rd line talent why waste him on the 4th line.