I voted Drai but I think it's any of those players except Matthews.
Nothing against Matthews, he's a great player and he's still building his legacy. But you can't ignore the playoffs and all those other players have been great in the postseason. Kucherov has two cups, Mackinnon and Makaar with one each. Drai has played as well as a player can in a losing cause.
Still lots of time for this to change. Matthews hasn't reached those heights yet but he could do it at any time. At this point in time though, he's just not in that other group.