Likely Schwarzenwald (the Black Forest) in Germany. Schnitzel with frys, late 1800s-style housing, dense forest, mountainous, lots of bodies of water, and heavily impacted by deforestation.
Pretty sure this was supposed to be a low-brow, irreverent, turn-your-brain-off story from the start. I would much prefer that it be TLed as it is so people can judge it on its own merits, not intentionally made worse because you couldn't handle your own expectations not being met.
Did you forget that the entire reason the plot exists is that her mother is completely uninterested in being part of her life? This chapter in particular is meant to drive home how their estrangement is so great that mother doesn't know what their own kid is really like, and the kid would rather...
Most oxygen is not absorbed when breathing. Otherwise, mouth-to-mouth resuscitation and oxygen recycling systems would not work. It's dangerous to breath the same air repeatedly as the effect compounds, but in this case there's no issue (besides possible water intake during transfer).
It's not even an exaggeration. The tobacco double standard was thoroughly ingrained in our culture up until just recently. Tobacco smokers often still get exclusive breaks to smoke, while testing positive for THC at all can get you fired on the spot from the exact same place. Legit know people...
Guessing she's the student council girl's love interest and/or "straight" man. She hates normies, lechers, and big boobs, and the other girl hits all three. The chapter also starts off with the SC girl, while not having her and the new girl interact at all. BTW was that a real game mentioned...