@Memories:
Blondie lost all her memories or most of them when BRS decapitated her "avatar".
She then lost consciousnesses and ever since then she felt like something happened between her and Yomi but felt bad telling her straight on so she tried to avoid her, and finally she asked her to let her go. This triggered another consequence. However the point is there, she didn't remember anything from before. It's possible she could have meet counselor-sensei years ago, probably soon after the accident, or even before it. She doesn't remember Yomi taking care of her and abusing Yomi.
This is especially visible with the team captain, she was taking counseling before she got the love letter and giving it, so after her "doll" was killed by BRS she lost consciousnesses as well and lost the memory of that. She says she doesn't even remember him.
We are now at the point where OVA started, leaving us with 4(?) episodes of main arc.
As for the OP, I actually like it a lot, I tried to find it on TT but to no avail.
ED song is also really nice.
One of the fansub group pages I visited actually had a comment like: 'too bad there is so much school girl crap cause the shooting the fuck out of things is teh awesomes.' I have a hard time thinking that a group with that attitude can possible do a decent job on an anime where they totally miss out on what "awesome" means.
Lack of understanding the base of the events, if it wasn't for the "school girls crap" there wouldn't be the alter-verse where we would meet BRS and everything that happens there.
The OP animation also shows a vicious cycle of the girls "Avatars", one aiming at the other while another defends the aimed one and so on. This actually shows the paradox here, you can't make everyone happy, but you can actually try to make a set level of acceptable happiness. One where everyone is content to a degree, but not satisfied.
I'm hoping for the ending to be what I am thinking it will be. If i'm correct, we are up for a nice surprise.