I didn't care for Norman being in town for like five minutes and four hot girls are on him and then a hot teacher flirts with him. At least with the guyfriend of the girl that likes Norman I see the makings of a typical bully/foil for Norman. But even the girl with CF is cute. I don't see how all these nice looking girls actually making nice with him, for what seems like non-sinister reasons at the moment, works for the kind of person we know Norman is going to become. I would think he would be extremely isolated, or at least feel that way. Perhaps he does, but it's not easy to register when cute girls just can't wait to hang out with him.
You thought that was flirting?
That's what well adjusted human beings look like when they are not actively using sex to manipulate the situation... Unfortunately they were accidentally using sex which acerbates the situation. Most women live in a bubble where they don't believe that all men are always constantly plotting to see underboob. Basically those 16 year old girls were acting like they were 10 and ignorant in a good way, where they think it's possible for men and women to have platonic relationships even if one of them is sitting under her fanny in the back of a moving car.
They were offering him automatic Ducky status because he seems harmless and of course the benefit of the doubt.