Noah's attitude wasn't foreshadowed as such, but it gels with what we do know about his character. I read his take and said "Yeah that sounds about right for him." He seems like somebody who has to struggle with what's awesome vs. what's practical a lot.

I guess the question is, what pragmatic complications WOULD come with Flint's mutation?

Driving (which Cass mentions), really anything to do with being Flint's current size, clothes, shedding everywhere, squirrel attention span (which has to be like an extreme version of ADHD), potentially a reduced life expectancy (northern flying squirrels, for example, don't even live that long in captivity: https://animaldiversity.org/accounts/Glaucomys_sabrinus/), health care challenges (Flint will need to find a very open-minded vet), finding future employment (outside of show-business, anyway)...

Dogs will seriously want to chase him, and at his size that is no minor thing to laugh off.

The social repercussions will be severe. It might not be so bad in that town, since all these changes and mutations are forcing most people to be rather openminded and accepting, but what about when he goes to college, or after that? Unless he stays in that town all his life a lot of people are going to react badly when they first encounter him.

Getting a job as a squirrel will not be easy. It is surely possible to find one he can do, and there may even be some tht he is uniquely suited for now, but they will be far outnumbered by jobs he is no longer qualified for. For instance, with his fur I doubt he'd be allowed to work in any sort of food service job at all. Even fast food, the last resort for income that nearly anyone can take if they need it, will be denied him.

I wonder if he'll have to worry about any wild raptors. (How much does he weigh? Could a golden eagle pose a threat to him?) At any rate, he's pretty low on the food chain. Between that and the social repercussions you mentioned, his travel opportunities will be seriously limited.