Dallas doesn't make that move...that doesn't help them at all for a run. You are giving up way to much for the elderly, shells of their former selves the Sedins.
I think the Sedins would fit great in the 2nd line slot with Gallagher and they are still serviceable players and fit the teams needs with one trade.
The Dallas move is if they are out. They are hanging on to a wild card slot. Low risk because Sharp isnt having a great year and is a UFA after this season, Dallas gets a pretty good young prospect back and a lower pick.
Spitball moves, unfortunately the Habs don't have ton of assets or capspace to make a huge move to put them over the top. They would have to somehow move DD(which would take an incentive(ie. 2nd rounder).