The one thing that I think Treliving should be trying to keep somewhat in the back of his mind; is trying to ensure that there is a "next wave" for the Leafs.
You look at the Dallas Stars as an example, been a very good team for a number of years, but now have Robertson, Hintz, Johnston, Stankoven, and Harley really coming into age to take that next step; while maintaining cap flexibility.
Leafs are starting to get up there in age. Their top 4 defencemen are all 30 or older. Their depth is comprised of likely journeymen defencemen. Matthews/Marner are 27 and Nylander is 28. All have played since 18/19 years old.
Knies is obviously in a great position age-wise, but if they can go out and get a guy like Brayden Schenn, perhaps without losing Cowan/Minten, it puts them in a really strong spot even for next year; given that they will have ELCs, and it's going to become harder and harder to get guys under $1m when every team has so much cap space.