1) Owen. She and Owen need to amke peace with each other. This seems to already happening. In any cafe, if Owen can accept the fact that the past is passed, I think Gwen will too.
2) Mordred. Mordred, Mordred, Mordred. Right now, she needs to accept his choice in love. She really, really needs to talk to someone modern, like Grissom, for that. Really, I think Grissom might be ideal -- he's in love, he's reasonable, he's male, they don't have awkward history, and he just strikes me as the type who'd be able to deal with her.
If Guin can accept Mordred/Galahad, I think that can lead her to accept that people make choice, and that those choices, have been made, and she just has to deal with those choices the way everyone dealt with hers.
3) Merlion. Hoo boy. Guin blames Merlion for making her abandon Bran, and she's not wrong. I think I'm gonna defer the solution to this issue to the dealing-with-choice solution ("The Light gives strange choices").
4) Bran. Gwen is never going to be over the fact that she couldn't see Bran grow. There's a lot of guilt over abandoning him, even though she assigns blame for that to Merlion, and a lot of need for a family. That Bran calls her mother helps. Seeing him all grown-up and Destiny-y may help -- I'm not exactly sure. Now that she's gained him as a son, I think she needs to let him go. It'll hurt, but I think she'll be able to do it more easily (that's not the right word, but) than one might expect.
So, to sum up. 1) Gwen and Owen need to accept their relationship as friendship, and accept the past as passed. 2) Guin needs to talk to some modern folks. 3) Guin needs to accept the choices of others. 4) Gwen and Bran need to play together again, and she needs to find out about his destiny.
And I had loads of fun character analysis stuff typed up, but my connection is sketchy and has already eaten all this once, so that's for another time.