Hi,
When we went a year ago with our family of 6, I made t-shirt with the whole Mickey gang on them that said "Aaron Family Vacation 2003" They were all the same color which was incredieble handy when looking for our group, which had small children in it and I didn't want to lose anyone. I used Disney Print Creations and Hanes T-shirts and the Dark Shirt Iron-ons by Avery. We received several compliments from castmembers as well as other guest and even lost my mom one time and we had a man, who was on the same frequency on our radios, find my mom by her shirt.
For your 50th Anniversary people(Bless them), I would do a shirt with Mickey and Minnie on it, with the expression "Celebrating 50 with Mickey!" Or on the back put "50 with My Minnie" for him and "50 with My Mickey" for her.
Good Luck and I hope this helps!