Re-read your post, and realized that you have five credits but are booked for seven.
Cinderella's Royal Table comes in at $54.76 after tax and gratuity for adults and at $33.60 for the Disney Kids. I got these prices from All Ears as it has been many years since I added this restaurant to the "never again" list for our family.
So, unless you get rid of some table service, what is the cheapest way to manage this. Since CRT uses up two credits, the question is, can you replace two single credit restaurants for less than $54.76 per person.
With the restaurants you listed, it is possible if you choose to pay OOP for 50's and WCC, IF, and this is a big IF, people are willing to drink water, choose less expensive options, and or share.
If the diners are going to order an expensive entree, ice cream shakes, desserts, and soda, then the least expensive option is to pay CRT OOP.
Since this meal is the choice of one part of the group, why not let them go, just them, and you guys can spend the rest of the day together.
Just because you go with people, does not mean you have to eat every meal with them.
Just let all the people going know, "Hey you have five credits, and here are the places we have reservations. You can use your credits however you like, pay out of pocket where you choose, or skip a few of these table service."
I have done the group thing where everyone tries to stay together the whole time, and it leads to the kinds of headaches you are having right now.
The meal in the castle may be the "Bees Knees/Can't miss event" for part of your group, but that should not mean that everyone has to shell out more than $50 for a sub-par meal.
If I were you, other than CRT, I would keep the meal reservations and let people choose whether to join or not. With CRT, you will need to call and cancel for those in the group who are not as thrilled with having the "experience" of eating in the castle.