@drawn_inward : back, and ready with my info!
We did Universal Islands of Adventure, Epcot, Magic Kingdom and Animal Kingdom. Li'l Z loved Islands of Adventure, but giving your girls ages and (I assume) interests, you're better saving Universal for when they're older. Having said that, I'll break down the other three this way:
Epcot- Li'l Z liked a lot of Future Land and meeting Baymax, and would have spent the entire day on Test Track if he could. He is also over 44" tall, so he can go on almost any ride at all the parks. There are a number of shows for all ages, and plenty to see that doesn't require heights. If your little girls are into the princesses, especially Frozen, this is a good spot to take pictures. The Frozen cast are in Norway, Jasmine is in Morocco, Mulan's in China, Belle's in France, Joy and Sadness from Inside Out are there, and I swear I saw Princess Elena somewhere, in addition to the usual Mickey gang. The adults in your group will like Epcot because the Food and Wine Festival is happening right now, and you can drink and eat your way around the world. It was yummy! Otherwise, I think your best bet is Magic Kingdom or Animal Kingdom.
Here's the main thing: how long do you have at the park? If you have all day, go to the Magic Kingdom. If you have less time, go to the Animal Kingdom. Animal Kingdom is a smaller park, and we did the whole park in 4- 4 1/2 hours. There are a lot of shows at AK, which might be good for the little ones, a gentile train ride to a petting zoo, several walk-through animal exhibits (yes, all stroller friendly) and a dinosaur park. The adults might like the Pandora/Avatar land, and Expedition Everest. Li'l Z isn't really a sit-and-watch-a-show kid, he likes more interactive stuff, so I can't tell you much about those, but he really got excited about seeing all the animals, lizards, bugs, and fish. There are character meet-and-greets, but no princesses. Now, Magic Kingdom has a TON of stuff going on, and lots of stroller parking. There are a number of gentle rides you can take the girls on, a ton of meet-and-greets, lots of parades and shows throughout the day is they need to sit. Magic Kingdom is far more ride heavy than AK, but it does have more little kid rides (Cinderella's carousel, It's a Small World, Winnie the Pooh, the train around the park, etc).
One thing I can tell you that you need to do if you're going to any Disney park: download the My Disney Experience app. (It's free.) This will be your best friend on the trip. It gives you a map of the park, shows you the wait times for rides or character meets (and it updates frequently), gives you gps and walking directions, shows you nearest restrooms, guest services, EVERYTHING. If you get FastPass (and I highly recommend it, ours was free because we stayed with Disney), you can book your Fast Pass reservations for rides or meeting characters through it. If you're doing meet and greets, I can't recommend booking ahead of time enough. The app also linked up to our wrist bands, which provides our park passes, and if you take any photos, you can see them through the MyDisneyExperience app and buy them (or not) at any time. No matter which park you go to, the app will save you so much time and headaches. We got to do soooo many things at the Magic Kingdom thanks to that app.[DOUBLEPOST=1508520025,1508519481][/DOUBLEPOST]Almost forgot! Princess Sophia is around, but I can't remember if she was at Epcot or Magic Kingdom. But Doc McStuffins and her toy hospital is in Animal Kingdom.