No worries on Sarah, I think she's my favorite of the initial group, maybe because she's the most "normal" of the group? I mean, the others are a best bud with no self-preservation, a succubus with almost no filter, an archangel that slowly learning to be more than just a weapon. Celica joins the next day but she's somewhat reserved at first.
I know it makes for more work to have multiple good branches, but I like the way that you've presented everything so far!