@Rodork Yeah, In that same page you linked, Fuu even said to himself as Miku was walking away, that he had to rely on cheap tricks to tell her apart... but two panels later see her clench her fist and Fuu's eyes open wide at that sight in the next panel basically saying to himself something is not right... that maybe he was wrong... and blurted out Miku. He's getting there... but he got lucky and read the mood. If he had not noticed the clenched fist and let her walk away, the whole dynamic of their relationship would have been totally different going forward.
As for Ichika, I'm going to let the arc play out. Everyone is wanting her gone because they see the scene where they see Fuu with Ichika and it was the defining moment that changed her life forever but even though it may have been had a big part... all kids at that age will want to find their individuality and want to separate themselves from others. So many questions left to be answered like what happened with Ichika and Fuu that evening and how they met, etc. Interesting how Nino also saw Fuu "Fuu-kun" that evening too but didn't connect it. That evening Ichika went to the lounge... was she wandering looking for Yots and thought she'd find her in the lounge with the boy and that's how they met?? People make it sound like she ran to the lounge to steal Fuu lol.
And as for Ichika wounding her that Yots gave up on Fuu and the promise they made together... Yot's after that incident, started wearing the ribbon and she worked HARDER at being the best telling her mom, "I've studied harder than anyone else and first place last time" remember? The lounge incident may have triggered her desire to separate herself from her sisters as far as identity but I imagine the death of her mom was an even greater life changing event... for all the sisters.
Did that moment ruin her life from that point on?? Lol no because in current day all the sisters are relatively happy and their love for each other strong as ever. So there's a lot more to find out.