How's Toronto affording Matthews, Marner, Nylander, Doughty AND Tavares under the cap?
THey wouldn't. Tavares isn't going to the LEafs. And even if Doughty weren't , it's unlikely they can afford Nylander , given the other contracts.
That said, they have a lot of contracts coming off the books after this year Bozak, JVR, Lupul is close to 15M and there is also Komonov, Fehr and Moore that's another 6m. So that's 20M. They have a some good kids they can bring up on ELC's and also, would get a decent player back for JVR and draft picks for Bozak and JVR.
Matthews will likely get in the 11M range and Marner 9, so if they elect to go for DD and 12, that's a risky move CAP wise, but on the other hand, they'd have an elite bonefide #1 in Matthews, a good (he was very good last year, esp defending) #2 in Kadri, a #1 D in DD, that's a pretty solid triad of what you need to be a contender. You add Marner and some of the other minor pieces that were good like Hyman, Brown and kids like Kapanan and Aaltonen , top young forwards who should make the team next year and getting Calle Rosen (D) was a good move. Adding Marleau in there and you have a deep team. They'd add a seasoned vet for the bottom line cheap possibly, esp for playoff experience.
And DD, like a lot of players, loves playing for Babcock and is shows in the Olympic games. It's just a matter of what choices Papa Lou and Co make. But it's not far fetched to thnk they could make room for DD, it's just a matter of what it would cost.