By Anna's thoughts, it's apparent that Akane has exposed her BL brainrot in public or another mixer before and that kinda makes her their own version of Ando, except she's not-so-secretly hot unlike him.
Meanwhile, the gyaru is actually a thot lost in more dangerous thoughts. A man-eating time bomb probably on-par with Yuu. We may not have her there in person, but she is there in spirit.
The surprise here is that Anna actually considers devouring Toshiki Ando. Probably the only girl who's even noticed him here. For a girl like her who sleeps around a dick's a dick, I guess. Plus she's had her fill of good looking guys. Hey, for all we know maybe Ando is packing heat, I guess that would be nice for her. Ando seems like he'd be a hentai protagonist in certain genres...
So MC's choices are:
- Fairly normal girl itching for a one night stand with him in particular
- Man-eating gyaru who will devour any man and leave after she's done having fun
- Busty fujoshi craving to see live man-on-man action while she watches from the side
I don't think any of the girls is interested in a long-term relationship, but if he's only there to test whether banging girls will pump his 3/100 up, he should pick one who'll actually let him figure that out. I mean, he's got a deadline to meet... (unless he's also interested in finding out if banging guys will also increase the number)