On the question rating level what's the difference between Family Safe and Non-Adult?

I don't get the specific difference between any of them, not detailed anywhere that I know of. However, note that almost all of the scale seems to deal with sexuality, so for example violence & gore could be non-adult but not family safe. Or maybe it's mildly adult, or adult, who knows.

Actually "Family Safe" is probably only rating that's easy, if it has no strong language, sexuality, violence etc. then it's family-safe. Of course, since "Non-Adult" is the default, I don't imagine anyone is practically ever actually using "Family Safe".