I think the friendship with Judith did have an impact on Charity/Pansy. I used to wonder about the change from homicidal jealous woman to self-sacrificing, caring woman myself...but I have to say I like the latter better.
I too wonder about why Blackwood didn't disappear after getting shot....all I can say is maybe the man really is a demon from hell or became one after Aristede killed him. If so, then maybe it's possible that no one even Petofi with all his powers can't dispatch the man so easily as with a gunshot.
I have to admit I like the scene between Quentin and Charity/Pansy. She loves him, but realizes he has to go in order for him to be safe. Would she have been so willing to see him go without her if not for Judith's calming influence on her? Probably not.