garbage offer

Only way Nylander gets done is a 1st pairing RHD with proven experience, preferably early 20s like Nylander.

Trash offer for William Nylander.

I don't even think that's needed. I think the Leafs just need 6 capable defenceman. They have two top pair guys in Rielly and Muzzin and currently have 4 other players with potential high ceilings in Sandin, Dermott, Liljegren and Lehtonen. Add Holl to the mix as the partner for Muzzin and you need 3 of those others to take a step and this defence could be a lot better than people care to admit.

I think that a young, proven 1RD would be more valuable than Nylander though. He's good, but he's a top 6 winger. Those are more readily available.

Just being honest marner will go before nylander just because of the money. Realistically they would need a young cost controlled player, a top prospect and a first (I know that is the ask for every player but when it comes to young players who are proven and have term it's a reality)
If I were Jersey I would definitely go hard after marner (again I dont believe they would have the assets unless they are giving up Hughes)

Severson, Zacha, AZ's 1st as a base

He's an elite top line winger.

No thanks

Thats a pretty solid return for Toronto

Sever son needs to be coming back if TO trades Nylander.

None of those pieces are remotely close to as good as Nylander though. Severson is a decent player but not elite by any stretch of the imagination, a mid 1st could be something good but it could also be nothing and won't be anything for a couple of years. And Zacha is just a 3rd liner. There is no point in trading a player with such a great contract who is still to reach his full potential unless you are getting a sure thing in return. Which that does not. Quality over quantity is a real thing and many don't get that. Nylander is by far the best asset in the trade you suggested. Its not worth it for TO to move him for that.