As per Consumers Reports, most of the drug stores use large bulk film processing labs. You really need to experiment to find a good film processor near you. For large volume processing, I have found York Film Labs to be of value. They are mail order and one can call them collect. Well, you really should take a few minutes and label the photos before you forget who all the people are.
Most people write on the back but be aware that ball point pens can make a mark thru the photo.
Felt tip pens are generally suggested. In many cases, one can select to get double copies from a roll of film. Or, just get a few copies of a particular photo. In either case, you will hopefully end up with more than 1 copy of the photo. So, I separate the photos, cut the negatives and match the proper negative with its cooresponding photo, and put both photo and negative in the photo storage envelope.