Regarding galatea....its a long shot, but she could also join the 7 and act in a support capacity. While her ability to influence the flow of yoki wouldn't work on AB's (not yet atleast...its still possible that with training she could increase that, just like the 7 increased thier abilities), it can still be useful to her comrades.

Rite now, the biggest problem for claire/miria/deneve/helen is that if they use too much yoki, they could go over the limit anytime. However we've seen galatea use her ability to pull clare back from the edge. It is possible that she could do the same for the others, especially if she trained and got stronger, and be a sort of safety net, allowing them to push thier limits and go a little crazy if the situation requires.

Btw, is Isely still alive? he was wounded during the battle with luciana or whatever, but i forget what happened afterwards.