Indeed, Xhekaj needs to sign this summer, while Guhle must sign a contract extension at the end of next season.
However, Xhekaj and Guhle's agents will certainly bring this contract to the negotiation table. If we compare just number 21, he's far superior to Vlasic.
In short, signing the defensemen will cost Kent Hughes a lot, especially as several other good young defensemen are coming up. It may seem far off, but Lane Hutson will need to sign in just two years. Time flies.
Then, there will be David Reinbacher, Logan Mailloux, and so on. The Canadiens' GM will need to be careful in his negotiations, but I'm not worried about him.