They're best friends.
I'm pretty sure Girl A is Fi-valuing, probably extroverted - if you say something she disagrees with morally, she won't let it slide. In general isn't hesitant to voice her opinion. She kind of demands responses from others.
Girl B is ethical, probably sensing? Always quite nice to people, but when you talk to her more you realise she has a strong dislike of many people...cares a lot about family, and places emphasis on symbolic gestures, like turning up for important events just for support.
I haven't gotten as good a grasp of Girl C. She's quieter, seems to largely go along with what Girl A wants. Friendlier to strangers than Girl A, who usually seems suspicious of them.
(on left, with Girl A)
Any ideas at all would be helpful, thanks!