Mike, Everything I can find on vac pac mushrooms says to cook them before freezing. You would never vac pac fresh mushrooms and store in the refer, they would spoil. As far as vac pac fresh mushrooms in general, I can't seem to find anything scientific that says a chemical reaction takes place with garlic and mushrooms. There may be but me and Google been at it an hour now and ...
As I stated there is an issue with anaerobic storage above 40°. I would say, if you are worried, cook them as described below and then do as you wish. I am not understanding how mushroom would, " make a decent liquid binder to replace the gluten item in the recipe. "
It would be helpful to see the recipe you plan to use. I have seen a lot of Protein based binders but not any with Wheat Flour and if the recipe uses Wheat Gluten, there are alternative protein binders you can use, Powdered Milk is very common...JJ
For storage, the mushrooms can either be steamed, blanched or sauteed before putting into a freezer bag or (even better) a vacuum pack bag. Get as much air out as possible, seal and keep them frozen until you’re ready to use them.Frozen mushrooms can always be directly added to your dish without thawing.