About sneaky deals with the weasels, why not sneaky deals with the ferrets? They might be willing to make deals without the weasels knowing if it can help them rise against their opressors (at least Iäve got the impression that the weasels live some kind of spartan life with the ferrets like helots. Ferrets might even be willing to ambush a few weasels now and then and sell their musk if the mice need it?