@Mia22 First of all, welcome to our little corner of the DIS. We aren’t the biggest group, but overall I have found the advice given here to be *accurate*, and based on Disney’s own posted rules. Some other places on the interwebs seem to be intent on telling folks all of the “hacks” for Disney… and while it’s great to know how many uses there are for a quart-size zip-lock bag at Disney World

you, me and most of the folks around here need real life, solid information we can plan around. Luckily, we can find that here, because everyone is aware of the consequences of not setting a proper expectation.
My own personal experience with ordering kids meals at table service locations at WDW has been mixed at best. Typically, if our (adult) family member asks the waiter if it would be OK to order from the kids menu, they will give 1 of 2 responses: either “I’m sorry, but we can’t really do that” or “Yes, but the meal will be priced at the adult portion rate”. I have also learned that appealing the “no” decision usually does not work, no matter how many pretty-pleases-with-sugar-on-top you add!
Most of the time, our family does not get the full ”value” of an AYCTE if you look only at food consumption. We go, knowing that we are paying for the atmosphere, character interactions and/or other features of that venue. We tend to seek out the type of experiences that are similar to Garden Grill at EPCOT, or Whispering Canyon Cafe at Wilderness Lodge. Those present “family-style” dining where it is still an all you can eat format, but a relatively fixed menu, and they tend to be a bit more accommodating (for example, they can bring the mashed potatoes out in a separate bowl if someone needs them to not touch the other food, or they can leave off the bbq ribs if no one is going to eat them). I have also noticed that planning those kinds of meals for “off-schedule” times (ie, lunch at 2:00 pm, or dinner at 4:00 pm, etc.) often results in a much more relaxed, easygoing atmosphere for everyone, including your server.
We have family members who regularly bring their own food, and while Disney kitchens can’t warm that food, or present it with the other food ordered, we have had no pushback when it comes to guest-supplied food at quick service locations. At table service locations, we would expect to see a “plate charge” on our bill, however in all honesty, we never try to take our own food into a table service venue of any kind at WDW, so I can’t speak to what might actually happen there.
I truly hope you all have a great trip when next you go to WDW, and that you can find several strategies here to help make the overall experience easier for you, and all of your family members. So often, we find that we have to create our own customized way of doing things when we travel; hopefully you find ideas that work for your entire family as well!