All of these a garbage aside from the Arizona deal

Arizona Trade: You're right that Chayka likes the idea of a steady top-pairing veteran to play with OEL (after all, that's why they traded for Hjalmarsson). Now that the team's blue line and net are healthy though, Defense is of less concern than Offense. Even if Arizona wants to add veterans, I don't see them swapping major Forwards for a Defenseman.

Toronto Trade: If you're right that Toronto needs to trade Nylander (or someone similar), they wouldn't be interested in a package of Grabner, Nash, and a couple picks in return. Nylander is a 1st line Forward (which his 5v5 numbers show) at 21 years old, and Leivo is a wildcard who could be fit for a middle 6/PP specialist role; together, the two of them are worth far more than a pair of rental middle 6 wingers, a 2nd, and a 4th. Plus, the only reason Leivo gets scratched in the first place is that Toronto has a logjam at Forward; why would they want a pair of rental Forwards?

Carolina Trade: You said it yourself: Nick Holden is bad. TVR is better, younger, and cheaper than him. The Hurricanes don't have any reason to make that trade

Vancouver Trade: There's a year-and-a-half left on Zuccarello's contract, and this season is already lost for the Canucks. Even if Vancouver wants to trade picks/prospects for veterans, I don't think they'd forfeit a lottery pick in this draft for the last year of Zuccarello's contract.