I agree with PP's recommendations--for a different character meal check out Garden Grill. For something with kid & adult appeal, check out the other TS and decide what matches your family's tastes.
My kids, DH & I loved Teppan Edo in Japan (it's a Japanese steakhouse; we had a great chef who made it really fun for them), Coral Reef (the big aquariums are really cool & we all enjoyed our food--but some people don't love the food here), and San Angel Inn (this one is dimly lit, with the Mayan temple in the background & the water ride going past). We liked other restaurants, too, but wouldn't send you there with young kids. These 3 all have something going on that would distract the kids. Biergarten is on our list for our next Epcot visit, but consider that one, as well.
You know your kids' temperaments and your DH & in-laws' taste in food, so just choose what will work best for everyone.
For quick-service in Epcot definitely check out Sunshine Seasons--it has a good variety of choices and some yummy dessert options.