Montreal rejects the first trade.

Why does Montreal want Perry? Why does Perry waive his NMC, leaves his home on the Ocean for the St Lawrence River during the winter? He doesn't

MTL wants him in order to acquire Comtois
If he doesn't want to leave, is there a way that we take a part of his salary without taking him?

I think it's bad cap management and bad for team morale to have a player "hanging around" for cap reasons. Habs would be 100 times better off forgetting about 8.6m Perry and try to sign Duchene at 9m.
And why trade Tatar for an iffy future. The idea is to win now...or least make the playoffs and a playoff run, no matter how short.

To answer you question you asked....No.

I agree with everything you said except the win now thing... MB stated that the futur of the organization was the priority... There's no rush in winning now with our top prospects coming in next season

It's actually not a bad deal at all parties, assuming the Habs want Comtois. Habs have ample cap space with which to buy out Perry. Perry accepts the trade because it would be conditional on being bought out, which gets him all his money and also makes him a UFA so he can get healthy and shop himself around with a chance to make a bit more.

And they can buy him out during summer... He'd cost something like 3-4m $ for 2 years... Not that bad

The team doesn't have the pieces to win now. Price and Weber are passed their prime, the PP is a joke, the 4th line can't buy a goal and the left D is missing 2 established top 4 dmen. I just don't see how this team can win 4 straight series against teams like TOR, TBL, WSH, PIT, NSH or WPG.
I wouldn't be surprised if it takes another 3-4 years before the team gets back into contender discussions.

When a suggested "win now", it's to get into the playoffs and give some the young players a playoff experience. Gee, on October 1st there are about 24 teams who know they have no chance to be Cup winners but they all don't into sell mode. Teams still try to win as many games a they can for their players and their fans.
Three years from now, if Habs want to see and Tatar is playing well, he still might be worth a first rounder at TDL.