If I understand correctly, you first postponed your wedding, then decided to get married in TN with no attendants.
Please correct me if I have misunderstood...but if I had paid money for a bridesmaids dress, gas to try it on, etc...then I was told neither me or the dress was needed...I would be ticked.
If it were me, I would pick up her dress and mail it to her. I think I would also be reimbursing the ladies for their dresses if they can't be returned.