The Signatures are more "upscale dining" and I would probably avoid them, even though most offer a steak.
Tony's in the MK is main road Italian. It gets mixed reviews here, mainly because it is not "special". Liberty Tree Tavern dinner is like an old fashioned Thanksgiving dinner. It is served family style and it includes turkey, ham, beef, stuffing, mashed potatoes, beans, mac 'n cheese, salad, and rolls and butter.
DHS has 50's Prime Time Diner which is old fashioned comfort food with fried chicken, meatloaf and pot roast.
We eat in the International Restaurants in Epcot, so I am not much help there.
Resorts that may be good for your family include the Whispering Canyon Cafe at the WL, the Trails End Buffet at Fort Wilderness, the Grand Floridian Cafe at the Grand Floridian, Cape May Cafe at the Beach Club, and ESPN Club at the Boardwalk,
These are just some
Check out the menus here on the DIS and also at allears.net