What really sealed the deal for me was when Hina got all stroppy about not being able to meet up on Sunday (even though she never even asked) and even after overhearing Hana making plans with her friend, got shocked/disappointed when she was invited to come as well
You're confusing Hana and Hina. Hina's tall, blond, gyaru. Hana's dark-haired, "short and round".
I'm sure Hana will turn around second to last chapter and be like "oh wow im really gay for you all along!" but right now I'm not getting any feelings of Hana liking Hina anymore than a friend.
I assume I should read Hina instead of Hana everywhere in your post. So Hina's obviously gay for Hana since chapter 3:
http://dynasty-scans.com/chapters/hana_and_hina_after_school_ch03#22
So when she says, "I'm still weird, aren't I", she's concerned with having a sexual desire for Hana, not with her obsession over cute things.
Unlike Hina, who is pretty clear with her feelings, Hana herself is going to take a while accepting her feelings over Hina. She knows she's attracted to Hina, but she's taking her time to realise the power and the origin of this attraction.
And I'm pretty sure that once Hana understands her feelings, just like in GF, it's going to take a while before she'll manage to convey them to Hina, because the latter will do everything she can to clarify if Hana is really interested in her in the right way.
So the characters are like this: Hina understands her sexuality and feelings but is oblivious to Hana's feelings. And Hana is oblivious to her own feelings for Hina. Therefore for them to succeed as a couple, first, Hana needs to accept her ownself, and then Hina needs to accept Hana's feelings for her are true and not her imagination.