First I should apologize for misleading the four people who read my analysis of Chapter 144.2. I told you that Fushi couldn't be the one in Funa's body and I was wrong. I genuinely didn't think that they would care enough to put any effort into their Funa impersonation. I'm sorry.
Sometimes my comprehension skills break down on the side of the road and I forget that regardless of what form they're in, Fushi has yellow eyes that are drawn in a unique way. I was also biased because I want Funa's knocker to be relevant, and that affected my prediction on what would happen next. Since no one this chapter made a comment on Funa's strange eye color, I guess the yellow eyes are just for helping readers differentiate between characters sharing the same body.
Although it seems random, Fushi's plan was actually something they've been thinking of since Chapter 143.1 at least. It was the first time they saw how Mizuha and Funa get treated by this group of girls and it made a big impact on them, although Funa's knocker surprised them before they could intervene. The plan formed fully after their conversation with Satoru, and the death of Funa's knocker set things up so that they could use a form besides the nameless boy's for a little while.
The way Fushi goes over to Mizuha at the beginning of the chapter was framed to be kind of creepy. Imagine the present era from Mizuha's perspective and you will see how disturbing it is when the person you're in love with tries to kill your mom and then presumably kills your new friend so they can stalk you in her form. It's like a fucking horror movie. Fushi's now essentially doing what Funa's knocker was doing: using her body to further their own goals instead of preserving her lifestyle.
No matter how Fushi approached this problem, they probably wouldn't have succeeded, but asking three girls who hate your guts out all at the same time is a spectacular fail. They only know what a date is from when Mizuha introduced the idea to them, so despite her romantic intentions they're hoping it's a friend thing, and now they've created even more misunderstandings.
Fushi's conversation with their teacher felt multilayered, because her advice could apply to the knockers as well as to Funa's life. Fushi has only interacted with the knockers in this era one-on-one, but even when they have an opportunity to ask all the questions they want, they don't get any answers. Maybe a hint that this strategy won't work on either problem. Their teacher also reminds Fushi that there are people worrying about Funa even if they don't say so—which sucks because it's too late for anybody to worry about her, and Fushi does have friends who are worrying about them quite a lot. The only way they'd even know that Fushi's still around is if Bon was updating them.
I'm happy to see Fushi making an effort to do something constructive on their own, but their plan's execution was so bad that they ended up pissing off Mizuha so badly that the left hand had to get involved—which was, ironically, not their intention for once. They believe that the hairband was what helped Tonari and Mizuha become friends, but that doesn't work at first. So start lying to make the hairband "special" and therefore more desirable. In doing so, they've taken the one thing that Mizuha was able to give Hanna to prove that she valued their friendship and turned it into something meaningless. Fushi barely knows these girls' names.
I reread all the chapters in the present era so I could better interpret Saki, Nagisa, and Kasabe's individual characters, because when Fushi talks to them separately you can see how they act when they can't rely on each other. When the group first appeared, Saki and Funa were at the center and closest to each other, always clinging onto each other and the ones who Nagisa and Kasabe were trying to impress. Saki was the one who stomped on Mizuha's foot both times, and she and Funa got into a fight because they both liked the boy who princess carried her. After that, apparently Funa blamed Saki for Rikuya rejecting her and so they ostracized her. Saki was likely the one who instigated this as well. She's the leader, and currently she's embarrassed by Funa because her knocker called attention to her bullying of Mizuha in Chapter 143.1. That's the "blurting out every thought that crosses your mind" that she complained about to Fushi.
Nagisa was originally in the position of appeasing Saki and Funa before they fell out. She was more invested than Kasabe, and after they chased Funa out she stepped in to take the place of Saki's best friend. But Nagisa says that Funa was the one who left, rather than being forced to leave. Either she's they can't get along because she took Funa's spot, or she's expressing resentment that she was forced to choose between Saki and Funa. Or both? It's unclear at this point, but her words felt angrier than Saki's, who's just reflecting her own insecurities onto Funa (and also Mizuha).
Kasabe is usually quiet, and didn't attempt to please Saki or Funa like Nagisa did, so I'd say she's newer to the group? She doesn't react instantly with negativity like Saki, Funa, and Nagisa, like when she started to respond to Fushi's greeting in the previous chapter. She also occasionally takes the time to consider why others behave in the way they do, like when she asks Fushi why Funa switched her opinion on Mizuha in this chapter. Judging by her strong reaction to Fushi saying she doesn't hate Mizuha, I'd say Kasabe actually likes Mizuha quite a bit. She's probably the only one in that group who could genuinely be friends with Mizuha and Fushi, but doing that would mean social suicide. None of these girls can do anything differently, because they each think they might get thrown out by the others.
Tonari and Mizuha's interaction at the end of the chapter is awkward but progress; Mizuha links arms with her, which she usually does with people she likes, and although Tonari looks a little uncomfortable she smiles at Mizuha and responds amiably. When she first appeared this chapter, Tonari looked somewhat lonely walking by herself. She's one of the people who's worried about Fushi right now, especially since she sees it as her job to protect them. I don't know if the left hand was dragging Fushi back to their group or to a different area, but if she overheard that it's Fushi in Funa's body she'll want to know what the hell is going on.