Meanwhile, my kids eat ancient grains (farro and couscous especially) and whole wheat pasta all the time at home. We typically order adult QS for the kids at Disney because the QS options for kids are so wretched. We're also careful about TS or sometimes pay OOP so the kids can eat decently. A week of mac and cheese and cheeseburgers wouldn't kill them, but it would probably cause intestinal distress.
Many of kids' likes and dislikes are cultural. While there are certainly kids on the spectrum who have specific issues, you don't see kids in France eating dinosaur-shaped breaded chicken, or kids in Japan eating microwave pizza as dietary staples.
Kids like salty fried food because it tastes good (see also the success of McDonalds across time), not because it is genetically programmed and at some magic day, a switch will flip and they will suddenly clamor for miso, or braised pork. While I understand that Disney may not be the point in time to push the issue, it's good to look at the habits you are developing in your kids and work on that at home.