Montour gets more
You think Cowan gets top 6 ice time right away?

Can't see Vegas trading a young NHL Dmen for a young NHL winger.
Age old question. Why does Marner waive to Nashville in contract year? Of course why does Nashville do the trade. Keep Saros, a former 1st rounder and have 5m in cap

Korczak is a very good young defender. The issue is that he is Vegas' 8D next season and loses his waiver exemption. They are tight on cap space and are losing a bunch of forwards this offseason, primarily wingers. Robertson would get a legit shot there and would be a very savvy pickup. Meanwhile, Korczak is a physical defensive defenseman who shoots right and has an immediate role in Toronto. This trade actually makes a lot of sense.

Also, the obvious stipulation in the Marner deal is that Marner would indicate a willingness to re-sign in Nashville. Sure, they can keep Saros and their 5 mil, but what good is that? Who are they adding for 5m that makes an impact like Marner does? Plus, they've got Askarov. Maybe he gets included in the trade instead

Why wouldn't Korczak be on Vegas's roster next season? Martinez and 5.3 contract will be gone. If he's an NHLer at 1.2m, as you indicate, why Vegas trade him
A "willingness to resign". No, it has to be signed contract. Marner right now is just fair value at best with 11m contract. There is no benefit trading good assets just to resign Marner.Just as good value can be as UFAs this season or next. Isn't that the reason you traded Marner.....better value for 11m.

Hanifin - Pietrangelo
McNabb - Theodore
Hague - Whitecloud
Hutton
Korczak

And if the Leafs trade Marner prior to July 1st (at the draft per say), it can't officially come with an extension. There can be a handshake deal, but it can't be official. That's the whole point I was trying to make. You seem to forget how good Marner is. The fact he's a pending UFA won't change anything, Marner is a superstar and if you want him then you're paying the premium. That's not a player you move just for the sake of moving.