@dokidoki
"just the fact in the early chapters where Rumi said that if Akira was a boy she'd like to date her already says alot"
i think you're reading a little too much in an expression said between girls, it barely says anything
Rumi has explained already in ch 26 that the reason their whole conflict happened was because she was forcing herself to act like her older sister, forcing Akira to be the "little sister" of their relationship, when Akira started to talk and spend time with Aoi, Rumi realized that Akira no longer depended of her like she did years ago. The whole point of the conflict was that Rumi always looked at her relationship with Akira as that of sisters
there are already various minor details that indicate that Akira might be going in the Shouma route rather than Rumi route, though both routes are still possible
ch 29. First time Akira blushes bcs of a boy
ch 36. While Akira thinks about how Shouma/Sahara was the first person to accept her when she first transferred(even before Rumi, ch 2 evidences that Shouma had already tried to talk to Akira before to invite her to play with the boys) she blushes and her heart skips a bear, even she doesn't know why
ch 39. Akira discovers that p*rn only confuses her, not understanding why boys are so interested on it
ch 44. Akira creates a male character that'd be the kind of man she would be attracted to