I like Kurosawa and Shiramine, they’re great together but it will take time to sort things out.
On the one hand, Shiramine is overwhelmed with the whole rivalry thing and is totally freaking out because she’s developing feelings for Kurosawa who seems to consider her just as a tool in her quest of being “normal”… it’s quite understandable she tries to push her feelings away (via her defense mechanism, the tsudere mode…) It’s cute how she acts when she’s reassured in 15th chapter with “I want to be with you. There is no particular reason.”
On the other hand, Yurine wants to achieve her goal to be “normal” and at the same time she doesn’t want her bond with Ayaka to end. I don’t know if it’s just me but I get the vibe she took things more seriously not because she listened to Ayaka’s complaint that she’s not giving 100% in their “competition” but just because she doesn’t want Ayaka to surpass her in anything to not break their bond but I may be wrong. It was an interesting part when she was trying to proceed with why Ayaka is special to her without denying that anyone who can “defeat” her is good. Despite her enormous socializing progress, she’s a dork just around Ayaka and it’s quite the same for Ayaka who drops the mask of model student and allows to be herself with Yurine. I just love how they’re in their bubble, enjoying each other’s company. :3. It’s pity the author will probably not develop a great reflection about perfectionism/self-development/self-acceptance and I agree that the time is mismanaged between all these pairings. It reminds me Virgin’s Empire where I wait an eternity to see Chie and Ai and still VE is more structured…
For the other girl, I don’t think she stands a chance with Kurosawa. Maybe she will make Shiramine jealous or something like that but I don’t see her as romantic interest for Kurosawa.