If memory serves correctly, here's what I recall:
If you didn't stretch and dry them, but have them rolled up nicely, fur side out, and frozen, the will easily last until the end of next year in the freezer. But no longer. I'm guessing they will get freezer burnt.
I think I recall reading that if they are stretched and dried that they will last until next year, but your problems will be keeping them in the proper climate and keeping bugs from getting to the hides. I don't think you want to freeze them unless you can get them in a sealed package, because of the freeze dry effect. You would want to keep them in a cool, dry, dark location that would be free of insects.
Perhaps someone else can add some better info to this.
Good luck.
M