I just haad a thought - Ocean might be planting these characters and having them recognisable, talking with NIka's friends in the background, because they're the ones that carry the gossip.
Think about mysterious stalker Cheeto she's at the shop when Bella's buying Nika clothes. Pizza goth girl is known to talk with Zara, and Nami's shouting about how Nika needs to stop fucking girls in the restrooms, maybe Zara hears this rumour, and doesn't know the full details (she wasn't in on the girl talk from memory). So for some of them, their 'job' might just be to show the walls have ears. And this might play a big role in how jealousy/cheating is uncovered and made plausible.