Whispering Canyon Cafe - Dinner - good choice for American food; not much in the adventurous category; the vegan skillet is excellent option for the vegetarian (I eat meat and even I enjoyed the vegan skillet)
Sanaa - Dinner - good choice for adventurous eaters; entrees may be a little challenging for the picky eaters if not accustomed to Indian spices; but the bread service appeals to almost everyone not allergic to gluten
Sebastian's Bistro - Dinner - I haven't dined there just yet, but it looks good and I plan to try it this year
Kona Cafe - Dinner - this used to be a must-do on every trip, but recent menu changes have reduced its appeal for me. Last two visits were disappointing to me, and I had upset stomach after recent meal there.
The Wave - Dinner - excellent choice for American food, and usually they have a couple of great vegetarian dishes. Not so adventurous.
Homecomin' - Dinner - I haven't eaten here, because to me the menu looks unhealthy with lots of fat and cholesterol. It definitely has a following and may be fine if no one in party has such health concerns.
California Grill - Brunch - I've had a few dinners here, but haven't been for brunch. It looks very pricey for a brunch but also looks like it would be fun and tasty.
Hollywood & Vine - Dinner - mostly American food; not so great for adventurous eaters and vegetarians; but maybe worth it for the characters
Boma - Dinner - excellent choice and one of my top favorites. Variety of options including adventurous and more standard. I was there recently with a meat-and-potatoes eater and a more adventurous eater, and they both found things to enjoy.
Crystal Palace - Breakfast - I like this one for standard American food; it's not what I'd call adventurous
Cape May Cafe - Dinner - if everyone in your party likes seafood, this could work; not sure what would be there for the vegetarian if they don't eat fish; I haven't dined here for dinner, although I've really enjoyed their character breakfast
Artist Point - Dinner - I've been once since it switched over to Storybook Dining. Entrees still great, as they kept the same chef. I found the new desserts to be very kid-oriented and maybe not so appealing for most adults. I really could have done without the one with the bright-colored fruity pebbles mixed with spongecake. I'll probably go again and will ask them not to bring that one, if they still have it. But who knows, your kid might like it.
Skipper Canteen - Dinner - This is one of my favorites and I think it has good options for the less and more adventurous. Great choice.
Spice Road Table - Dinner - I haven't dined here yet, but the menu looks great for the adventurous; could be slightly challenging for the picky eaters, but probably doable.
Coral Reef - Dinner - I like the views here, but found the food a bit underwhelming, though not bad. I'd go again sometime for the atmosphere and keep my food expectations low; then if it's really good, it would be a pleasant surprise.
Tusker House - Lunch - this is another that used to be a must-do every trip for me, in fact it was my overall favorite restaurant at WDW.
But recent menu changes have made it less specialized and more generic. Not as much for adventurous eaters as there used to be. Still a good choice for the child, but your adventurous eaters might find more at Tiffin's.
Cinderella's Royal Table - Dinner - I haven't dined here since it was King Stefan's Banquet Hall, so cannot speak from experience, but most reviews I've read suggest the food is not worth the price, and you're paying more for the atmosphere and experience. If you go in with that attitude, as with Coral Reef, I think you'll be fine.