The way of the witch for our Beatrice begun with the breaking of the vase, because after that she wanted Virgilia to become her teacher. So because she herself destroyed the vase... She is Battler herself and that's Battler's sin.
Probably not...
I was thinking, if EP7 is going to mirror EP3 somehow, someone is going to find the gold and becomes the new head and the witch, right? The new blonde has the head's ring, so s/he must be a new head. Maybe the new blonde is younger Krauss, and becomes Krauss-Beatrice (or whatever a more manly name would be)?
If the new blonde is a girl, it's probably Jessica in some form. At least the character must have something to do with her family, as there's so much similarities. I like the actor theory, too.
It seems like the whole thing about Akujikishima has been forgotten after EP2... Does it have any relevance to the plot except for the spirit mirror anymore? There's the theory about ghosts, but I don't like them randomly appearing to people and talking to them. The medium theory is around the border of acceptable for me, though.