Hi Sarah,
Welcome to the Disney Parks Moms Panel and thank you for your excellent question. I’ve got a family of adventurous eaters too, so your question is near and dear to my, uh, stomach!
The first bit of advice that I would give you would be to tell your server that your family enjoys exotic tastes and spices. Although the kitchen isn’t always able to accommodate your request to spice things up, especially during busier times of the year, I’ve found that making this request has sometimes led us to get dishes that have been slightly tweaked in order to make them spicier or even more authentic.
Some of the more “adventurous” Walt Disney World restaurants that we’ve enjoyed that aren’t on your list are, in no particular order:
Sanaa at Disney’s Animal Kingdom Lodge - Kidani Village, J
iko - The Cooking Place at Disney’s Animal Kingdom Lodge - Jambo House,
La Hacienda de San Angel at Epcot,
Paradiso 37, Taste of the Americas at Downtown Disney. Another Signature Restaurant that I’ve always found to have some pretty interesting ingredients and flavour combinations (with some absolutely delicious sushi) is
California Grill at Disney’s Contemporary Resort. Even though it can't be characterized as an "ethnic" restaurant, your family might really enjoy a meal there too!
Have a Magical Day and bon appétit!
Lynne