1 Who's sub did you watch?

2 Er, Whose.  Sorry.

3 Ayako. (Which badly needs an update. In the early episodes they really botched a bunch of the names.)

4 I'd like to see the story behind Brioche, who I found far more interesting than any of the main cast. It also seemed like her backstory was far more "serious" than the main story -- at various points she refers to everyone else as children (which, considering she is a few hundred years old, would be a just perspective), but also their wargames are child's play compared to her world.
Also, I love the way her keigo speech sounds. It helps that she is voiced by Youko Hikasa, who also voiced my favorite character in several other series.

5

Both Brioche and Yukikaze use archaic forms, and I gather that's intended to imply that they're both quite old.

I think that if there's a sequel, it's going to be about the cursed swords, and Brioche and Yukikaze will be featured more heavily.

6 I think it was a samurai speech, not keigo.

7 Pete, yes, that's correct.

8 I thought I'd deleted the word keigo when I realized it wasn't right, which is why that sentence is odd!
Ah well. Here's hoping for a sequel.

9 Well, I will give it a try.  Looks like IB has a nice complete set up.