This is all in the possibility that Seattle picks Chiarot. Obviously this would be possible by trading Chiarot as well, but there is a 0% chance that Bergevin does that.
Montréal trades Byron, the other team buys him out, and he re-signs in Montréal. It saves the habs around $4.5 million in cap space and actual money over 2 years. The other team adds $4.5 million in actual money and cap hit over 4 years. The comparable for the compensation is Marc Staal, who costed less real dollars but had a higher cap hit. Byron himself ends up with the exact same amount of money as he would’ve had anyways.
And yes, this only happens if the habs aren’t outbid on Martinez. Although if need be they could give Martinez a bit more money and sign Merrill instead of Hamonic.