I have to translate the other 2 clips I made (not today, too tired), but Chifuyu says something weird/cryptic at the end of her introduction. She says "I wonder if I've become strange... no, it's just those two who are strange, right?" when noticing she feels kind of jealous watching Rikka happily eat takoyaki given to her by
Karin.
Call me a creep, but there are pretty much only 3 times you use okashii (strange) in Japanese (haha):
1) When someone is quirky/weird/different compared to everyone else, they say they're an okashii person.
2) When a character falls in love (especially BL/GL) and they're tearfully like "You're making me strange!" when they have a dramatic fight and almost break up.
3) When a character begins to fall into sin/depravity, they say they feel strange.
So yeah, high school gal love triangle confirmed.