I agree with Luke's Mom being from Alderaan. One concern I'm working with is that if she starts as a daring part of the team but then sent away when the storyline is better served by Anakin and Obi Wan being alone. The problem there is there Anakin is her strongest link to the story...but he needs alone time / with Obi Wan.

And ultimately, if after being a central heroic character she is left to care for the babies, something of a damsel in distress, I don't know that that serves the gender dynamics very well.

The only way to preserve the strength of her character that I can see so far is not to have her take a leading role. For something of a model, see "Butch Cassidy and the Sundance Kid," where Etta Place (the girlfriend) is returned to again and again.

My working draft has her as apprentice to Alderaanian scouts searching for Obi Wan. She will be more like Luke, young and unsure of herself but not afraid to use a blaster if need be. But rather than become a great hero, she maintains the more innocent character Luke would have had.

I'm still not sure how to work her into the story sufficiently and set her aside without making it feel like she's being set aside.