Are the Leafs tough enough?
No.
Have to protect the Matthews, Marner and Rielly to have success in the PO's. If they play TB of Buf in the first round they should be ok because the can compete skill for skill but if they play Boston they are in trouble. The Bruins can compete with them on skill and beat them up if they choose to so which they probably will. In the PO's you need skill and toughness which the Leaf's have one part of the equation. As a Jet fan this is where the Jets have the Leaf's beat for PO success. The Jets can match any team on skill, speed, depth, size and toughness. They can hurt your best players and defend their own best players and still match your team's skill. The Caps did this last year. they could match any team as the biggest/toughest skill team in the PO's which gave them the edge to win it all. They had the skill, size, depth, toughness, and experience to be the best.
Toronto needs at lease one player that is skilled enough to be a contributor to the teams success and still be tough enough and big enough to protect their top players. They get that and maybe a upgrade on D they may be favorites to win it all.