Teams don't trade 1st overall picks. It is just not happening. The amount VAN would have to trade wouldn't make sense for VAN and the amount VAN would offer wouldn't make sense to the team holding the pick.
CGY offered COL 6+22+28 for 1 in 2013 and it apparently wasn't even close.
If I have to stretch and think of a crazy EA NHL tier situation where it'd happen, it would be Edmonton winning and Vancouver trying to solve all their problems for a re-tool in one trade.
-1st Overall
-Milan Lucic
-Brandon Manning
-Stuart Skinner
for
-9th Overall
-Bo Horvat (cost controlled 2C)
-Chris Tanev (Rental RD, possibility for an extension)
-Thatcher Demko
Giving up the 1st overall lowers the burden of the Lucic cap dump because theoretically, Jack Hughes on his ELC should be a major cap advantage in itself since he should be a top 6 forward for all or most of his ELC but he'll be paid 3.6M or less (depending on what bonuses he hits).
Edmonton would basically fill 3 important direct needs on their roster next year, and they'd hugely fix their cap situation by removing Lucic and adding Horvat who is on a very good cost controlled contract for many seasons. Instead of adding Hughes who may or may not make an impact right away, they'll add 3 players who should make an impact in 3 positions of need, two of which should be on their team for the better part of the next decade.
They'd also get a top 10 pick to mess up with, so they wouldn't lose out on the fun of drafting relatively high and having it lead to nothing.
Again, super EA NHL unrealistic trade, but that's the way it is when you're talking about trading 1st overall picks. There's probably no way to make it work for both teams, so it never happens.