Aya-chan-senpai has been brought up again! Twice in the same chapter too, so I'm assuming her and Yazawa are going to get their own storyline developed too. You can see when Yua mentions texting Aya-senpai, Yazawa uncharacteristically stutters a bit, so I wonder what their relationship is like currently (like if anything happened before they lost contact considering how close they seem to be) and what Yazawa has in mind.
Also when she gets the offer and is asked to be in a girl band, she immediately runs off saying that she knows a drummer girl. We already know from the flashback a few chapters ago that Aya-senpai plays the drums, so Yazawa clearly wants Aya-senpai to be with her in the future, almost like it's a given, despite her currently deliberately delaying texting her for whatever reason.