Seivarden is the one I'm the least sure about. It doesn't bother me, I'm more curious about it. After canon it's not really clear what she's going to do other than hang around Breq, and I took that last part away. I'm guessing it will depend a lot on the people around her. If there's a theme then it's having her deal with emotional dependency and to some extent recovery from addiction.

For Lucille it's more figuring out who she is when people actually love and care about her. Even I'm not sure who that is, but I do think having her interact with people that she have become close to is working.

The other two are more tied to canon, and I don't really see anything I'd like to explore with them right now.