Welcome to planDisney Suzan!
Wow, with 16 in your group you have your very own Mickey Mouse Club! I think matching shirts are definitely needed!
With this big of a travel party, I think the best thing to remember is to be flexible. You all need to be "okay" knowing you can't do everything together all day long. I would plan to arrive together, get that perfect family picture in front of Cinderella Castle, then enjoy one or 2 attractions as a group. I suggest
it's a small world followed by the
TTA PeopleMover. Then, split up to do your own thing until lunch. Try a Quick Service location such as
Cosmic Rays Starlight Cafe or
Pinocchio Village Haus so each small group can order their own meals then you can all sit together and make afternoon plans.
After lunch, I would do the same thing, heading to Carousel of Progress or Hall of Presidents. Break off again, then meet for dinner. If you would like a group dinner, try to get 2
Dining Reservations for 8 people each at someplace like Crystal Palace (a buffet) where everyone can choose foods they like.
For the grand finale of the night, plan a spot to meet to view
Disney Enchantment. Meet about 30 minutes prior, bring snacks to share, and enjoy the show. I think having some break-off time throughout the day from each other will make it easier as everyone is not going to be going at the same speed and wanting breaks at same time. But, do what works best for the majority of the pack!
As far as parking, there is a daily fee to park in the
theme park parking lots. You can see if your off-site property offers any transportation options. Other than that, you can try to take as few cars as possible, but there's just no getting around paying for parking if not staying at a Disney Resort hotel.
Wishing you and your magical travel party a wonderful day in the Magic Kingdom!
Cathy