I know you all have a hate boner for Hana
I don't hate her as a character. As a person I wouldn't trust her at all is what I'm saying.
She's one of those types you'd always have to worry whether they stab you in the back or not. Yes, Hana supported Aya very much so far (because she's an oneecon) and sure, she gave us the hug show and such... I mean, the results are what they are, but objectively speaking she did all that with evil intentions. That is to harm Sou emotionally and - ideally - make him get lost. In extension she wanted to get Aya disillusioned, but as I mentioned earlier:
If Hana's plan had been successful and Sou would have reacted like other boys and even dropped out as a result, then the backlash would have hit Aya in the face. As the team leader for a one day class exchange she let that happen. So, if a boy she guarded for just a single day would be harmed and/or quit after that, then Aya would have suffered twice. First, because her dream guy would be gone and secondly because the school might have held her responsible. Not to forget, how would Sou's original team have reacted. Miku and Hinata would have teamed up for murder and Kana surely would have used her family connections to get them expelled.
One could say Hana didn't think it through in the heat of the moment. I agree, she did not. But the really nasty part comes after Sou hugged Hana straight. She more or less said that she wants have Sou's firsts, and all of them if possible. And then literally hand the leftovers to Aya once she's done with him. Okay, she wouldn't actively harm Sou anymore and it's her inner delusional self talking there - but nevertheless it should be truth in that. This is kinda disrespectful to both Sou and Aya. That's why I called her a hebi onna...
And lastly, yes - Hana is Aya's support but that might be a thing of the past sooner or later. It could be that the relationship between the sisters won't remain as-is. Hana was never Aya's rival before but now she set her sights on Aya's love interest and that might cause frictions, depending on how aggressively she pursues it. We will see how Kisa plans to let it develop.
...and by the way:
Grr... if only Hana wasn't such a two faced hebi onna
I put that smiley there for a reason. Hana is absolutely adorable in that picture, complete 180 to her usual icy poker face. If he can look at that, I can understand why Suzuki enjoys it. I also think that Hana makes Aya shine more. Konno Aya is quite capable on her own, there's no way she'd be the grade's rank #2 otherwise, but Hana's support emphasizes her strengths - in a way the two are equals and opposites. But I prefer Aya because of her looks and personality.
And honestly, I would want to make Aya cosplay as a classy catgirl, putting her in a cute, pure white onepiece dress and get her to wear some stylish fake glasses. Maybe even let her try different hairstyles, with her mane there are lots of styles she could wear along that. Though her usual braid would surely fit nicely as well.