Sit down dining will basically be whatever Disney owned restaurant interests you. You'll never find a better place to be GFCF than WDW. Your kids will feel like royalty.
For CS, here's where we typically eat.
resort: food court
MK: Columbia Harbour House, Cosmic Ray's
Epcot: Sunshine Seasons (this place is must do for us every time)
DHS: we book a TS lunch though the chicken tenders at all the CS locations are tasty and then we eat dinner back at our resort
AK: we book a late breakfast or early lunch TS at Tusker House and then we eat dinner back at our resort, though I hear great things about Flame Tree BBQ
Also keep in mind that the turkey legs are GFCF so they make a quick and easy CS meal if you don't want to deal with lines or waiting for a manager.