JT earned his contract at that point in his career, turning down significantly more money to come here. He also chose Toronto, not the other way around. A major distinction.
So, even when his numbers aren't always there, he is working hard and driving the net. He had the courage to jump into the fishbowl. I'm loyal to such players and commend their courage (relative to the application of such a term to sports) as they didn't take the easy, stress-free road.
All the other three IMO are overpaid to varying degrees simply due to the control the Leafs had at the time. Matthews, the least overpaid of the lot.
From a purely business perspective, it can be argued that no Leaf is overpaid as the franchise is the most valuable in the league in terms of dollars. However, from a practical, logistical, "Cup seeking standpoint", I would personally have taken a different approach than Dubas from the initial negotiation with Nylander, to set the boundaries (it would have been different had this team won a couple of rounds).
In the end, I've said that some of Dubas trades and tight money pickups have been excellent. Those early contracts were always going to bite the team barring a sizeable increase in the Cap.