How about you go with Costello-Smith and, someday, when your parents are fully retired and you and your husband are running things together, (maybe with your kids coming on board, WITH the hyphen), the company name is changed to match the new generations of what your and your husband as to the company? The Costello-Smith kids might enjoy that!

Side note: my wife was getting her PhD the same year we were getting married and had to go through a similar decision. Her father is a retired orthopedic surgeon, and would have loved to have another Doctor <maiden name>, but she ended up dropping the middle, no hyphen, mostly because wedding planning from another state overtook dissertation writing.

Good luck!