Furukawa's an interesting one, because it feels like she really just wants acceptance, and to latch onto "the popular/top position" person and ride their coattails.
S'why she was a lackey for Noa, and why she's suddenly so willing to go the distance for Himari; she sees success and power and acclaim, and desires it, even if she can only bask in its proximity and catch the afterglow.
So I actually think she's not intending anything malicious in what she did in this chapter at the aftershow meet-and-greet; just like she thought she was friends with Noa back in school after becoming "the one recording everything", she thinks she's Himari's friend after assisting with turning over all the video & photo stuff, and helping go after the other bullies.
She's clearly not a good person, but she's the one who feels like it wasn't about the bullying, so much as being accepted by the "in-group". She's not inherently malicious, but she's amoral, because it didn't matter who suffered so long as she could feel included and like she had friends. It wasn't even about "not being targeted" with her, like some of the other classmates; it was actively "being valued".
Though thinking back, there's a Chekov's Gun-type plot device in that one "pre-graduation video" that she apparently didn't hand over to Himari, and the way she and Noa were talking, it sounds like something potentially really bad. I have a feeling it'll be a trump card of sorts for Furukawa if she gets targeted by Himari and Kitami next, and could spell trouble for the two of them now that Himari's getting more and more recognition for her idol activities.
10 chapters left though, I believe, and still a lot of stuff to resolve. I'm betting we're getting at least one more death, what with the 'dead idol' foreshadowing, but I'm curious who (and how many), and whether Himari & Kitami will actually both get out of all this alive and intact.