I totally understand wanting to avoid the sometimes craziness of a character buffet on your first night!
Tony's has an adorable "Lady & the Tramp" theme. If your granddaughter & grand niece are collecting autographs, you can give their autograph books to your server, & he/she will get Lady's & Tramp's autographs for you. Lady & Tramp "hang out" in the kitchen!

Tony's doesn't always get great reviews on this site, but, while it's not one of our "every trip" restaurants, we do enjoy it. Our younger DS really likes the Mickey ravioli. I like the shrimp scampi - it's a lighter dish & always tastes fresh to me. Due to reviews, DH & I tend to stay away from the "red sauce" dishes. He normally gets the pork dish. And we like the Tiramisu for dessert! We've never had bad service. We also enjoy sitting in the sunroom area. And being right there on Main Street would be fun for your first night!
You might also consider
Liberty Tree Tavern in the Magic Kingdom - the food is traditional "Thanksgiving" fare & is served family-style. The setting is early colonial American.
You could also try either the
Grand Floridian Café in the Grand Floridian or
Kona Café at the Poly as 2 other possibilities in a calmer setting.
Whispering Canyon Café at the Wilderness Lodge is a fun option too & is just a boat ride away from the MK; however, while it's a fun experience, it's also a loud experience!

For dinner, there is an all-you-can skillet that is served "family-style."
And another possible character meal is
1900 Park Fare at the Grand Floridian. It's a buffet w/ the Fairy Godmother in the lobby, & Cinderella, Prince Charming, & the stepsisters making their rounds in the restaurants.
Crystal Palace is one of our "must do" character meals, but we normally have breakfast or lunch there. I'm usually not a fan of buffets, but I like this buffet because it has some "not-so-typical" buffet items. However, it can take the characters a while to make it around to all the tables. And it can be one of the louder character meals as well.
We prefer breakfast at
Chef Mickey's to dinner.
Hope this helps some!