I'd make every one of these trades if the other teams were willing.

Vanek > Desharnais - But get 3m in cap relief.
Statsny > Plekanec - But save 1m in cap relief.
Yakupov > 2nd rounder - No brainer. Even if Yakupov doesn't pan out, 2nd round picks are traded away for rental players like Stempniak, Stewart, etc. I think a former 1st overall pick is worth taking a risk on.

I don't think you know what you're talking about.
Vanek for Desharnais is a ridiculous concept, considering Desharnais had 29 points last year and stands at 5'6", while Vanek is stuck in Minny with a NMC and $6.5m, while scoring 41 points. Montreal is planning on rebounding this year and they have the LW depth to do so, with Pacioretty as the #1 and Eller as the bubble #2. Pleks had 54 points, I think, as a solid defensive forward. He's a legitimate #2 C and is a beast on the PK. Even as a bust, Yakupov is worth more than a 2nd round pick. They would probably want Noah Juulsen at the least.

Also, why bury Beau on the 3rd pairing? Or Carr on the 4th?

Minny wants to get rid Vanek badly so there options are buyout or trade. If Vanek was willing to be traded to Montreal, this actually makes enough sense to work. They rid themselves of half of Vanek's salary and get a decent player in return and even if they dont want DD, Buy him out. You just reduced your buyout amount in half compared to Vanek's contract. I know everybody hates DD for being small but the guy works his butt off, never gives up, never says anything bad, never plays bad enough to get benched. Something Vanek has been noted for. The only benefit here for MTL is that they get a guy who can score more then DD can and isn't as much of a pushover come playoff time. Since there both 1 year deals, the risk factor is very low.

Eller is not a top 6 LW. He showed that this year. The guy is just not talented enough offensively. Where Eller can show some real value is his 3rd line center capabilities. That is his perfect role and he did it well while he was there. Playing on the 2nd line LW just wastes what he's actually good at.

Plekanec is a solid player that doesn't get enough credit. The guy puts up solid numbers and plays both ends of the ice extremely well. With that said, he's turning 34 soon. Statsny is only 1M more expensive but 4 years younger. Both contracts have 2 years left. This should be a no brainer as Statsny has more upside than Plekanec does and is physically bigger. Thinking farther than this year, this trade is a clear win for MTL.

I do agree though that Yakupov is worth more than a 2nd rounder. Frankly even if the trade was for Juulsen straight up, i'd make it.