Really feels like Hinaki was the protagonist all along and the other 2 are just side characters to her story.
She pretty much is the only character who feels like a real person, the other two's development has been too sudden and unnatural for them to feel like actual people to me.
It's like they are robots who had the "Become a couple now" switch turned on by the author.
Let's see what the final chap has in store for us. Probably one final talk between the 2 girls about their thoughts about Aida.
I don't think Hinaki is gonna suddenly turn around her ace development at this point.