gee Tweak while I am certainly no veteranarian I can certainly see where you are coming from. Of course I can't give medical advice (not that I would know what to give anyway

) but in my personal opinion it is a tough call... I think I would wait a few months then adminitister the vaccines. That was he is protected just in case, yet if the previous owner did give the shots at least they wouldn't be so close together. (hope that made sense.)
I realize the ultimate decision is up to you, but I would have thought yuor vet would have had a little better advice to offer since the distemper is hard on ferrets. Is it possable to call a different vet for a second opinion?