The Toronto trade would be the worst thing for that franchise to do. Nylander and Marner are their future at wing. They don't need two #1 centers and no top wingers. That'd screw them over in the long run.

I'm not sure the Leafs are even going to interested Tavares when he a UFA in two years. (cap space) Sure as heck, they aren't trading two prime assets to get him for a couple of years.
Bruins might not even trade Hamonic for Carlo straight up, never mind giving up assets for Ladd.

*Looks at Marner's stats as a rookie compared to Tavares'* Nah, I think the Leafs will pass and just sign him in 2 years

If the Bruins wouldn't include Carlo in a package for Landy or Duchene why would they do it for Ladd and Hamonic?

Andrew Ladd who has done nothing for you this far and is a complimentary player, and Travis Hamonic who is a solid Defensemen, that I would love to see in Boston but retaining both their salaries isnt going to sweaten the pot anywhere near close enough for Don to give up Carlo, Beleskey, Heinen, Senyshyn, and a 1st. Carlo's stock is way up right now as it should be. the way he is looking right now he could shape up to be a very solid number 2 D man. Beleskey and Heinen are both liked in Boston but that doesn't make them untouchable by any means. But Senyshyn at the time of the 2015 draft seemed to be a reach with the 15th overall pick but is on track for back to back 40+ goal seasons with the Greyhounds in the OHL so somebody would have to make a really good offer to Boston just to get Senyshyn. and you want a 1st from Boston who probably wont make the playoffs.