Man, that is a list of modifiers. And it’s not even complete (what about not-adult?) or true in every case (you say not-fat, but then you have things like Jamie Oliver getting shit for nutrition plans because it’s not American to be healthy apparently).
I think it may be more useful to not try and precisely define the bounds of what “people” think of when they think of a Real American. It’s individualized to a pretty exceptional degree, and it’s a lot like genre definitions - the borders are really, really fuzzy.
More useful, I think, is the concept of your social sphere. “Real Americans” for any given individual include themselves and the people in their lives that they care about as human beings (“Real American” being proxy for “Positive”), as well as people outside that immediate social sphere that remind them of people in it, and people they see in media.
Thus, that list o’ qualities human being simply reflects the commonality of those traits in combination, and the way the way people with those traits control portrayals in media.
Which is why the most powerful weapon in this fight is diversity. If you know a gay person, you’re more likely to accept gay people. If you know an ex-con, you’re more likely to accept ex-cons. If you know a black person, you’re more likely to accept black people. And on and on.