Hello, Kimberly!
We just had the opportunity to dine at T-REX A Prehistoric Family Adventure, where the food was spectacular and the ambiance was really cool!
I don't think that it would be too scary for your little ones, either. When the meteor showers arrive every 20 minutes or so, the lights drop a bit and you can see some movement of the animatronic creatures and meteors streaking overhead, but it's not too intense. If you're unsure of that experience, T-REX's sister restaurant, Rainforest Cafe, is very similar, but with a jungle theme instead.
On the other hand, if you haven't tried
The Crystal Palace Restaurant at Magic Kingdom Park, you might want to consider booking a reservation there; it's a family favorite! Not only is this restaurant very convenient, being located inside MK, the food is really delicious, too. It's a buffet, much like Chef Mickey's, so the kids can eat immediately upon being seated. Of course, the highlight here is seeing Winnie the Pooh and friends, too!
Another favorite of ours is
Akershus Royal Banquet Hall, in Epcot's Norway Pavilion. There, your little princesses can dine with Disney Princesses while enjoying a really lovely buffet. All Guests also receive one professional Imaging Package per group, with a professional photo of your family with one of the Disney Princesses upon entering the hall. What a great keepsake!
There are so many other possibilities here, so if you're still unsure or have any additional questions, please just send them my way. I'd love to help!