Not all the ahl players are under contract with the nhl club and most ahl teams aren’t owned by the nhl team like Ottawa’s is. This won’t work.
What difference does it make contractually if Belleville relocates for one or more seasons to Ottawa? AHL teams relocate all the time, it isn't like players are let out of their contracts because of it.
If everything contractually promised to the AHL players is given to them (Pay, travel, living accommodations, etc) what difference does it make if they relocate to a different city for one season? If anything, it would end up being an improvement travel wise if they have a schedule that mirrors the NHL team, and thus get to travel with them.
The entire idea would be that AHL teams would temporarily relocate to their parent clubs city, since there would be no live AHL gates anyways, it isn't like it matters. While they'd have to get union approval, I doubt that would be difficult to do. The issues wouldn't be between the players, it would be between the AHL owners and NHL owners. They'd have to come to a fair agreement about how it would all be handled.
Everybody involved from the NHL, NHLPA, PHPA, AHL, franchise owners, etc, would have have incentive to make something work. Especially if the NHL opts to go to a series based schedule to reduce travel, having farm teams travel with parent clubs and mirror their schedule would be extremely efficient.