So this has to be a quick theory so. Let's start.

I'm guessing Sabine's brother will have to go to get her, Kanan and Ezra. Her mom will speak to Sabine about the darksaber. She will have to fight Gar Saxson to prove she's worth. She will defeat Gar and her mother will help the rebels and Sabine will have her biological family back.

Sorry about how short it is it's been a long week and it's only Wednesday.

Till next time Emily out.