Well, I don’t know if you have watched Rebels, but Ahsoka seems okay after Order 66-she feels guilty about Anakin but is on the same thought as Obi Wan that Vader killed Anakin. Sabine’s story would be really interesting to me, because she was protecting Lothal at the end of Rebels. So-did she leave to help the Mandalorians while the Empire wiped them out? Did she even know about it? Was her family wiped out? I think Sabine would want to help reclaim the Darksaber. She gave it to another Mandalorian to lead all the clans, so she wasn’t the one to lose it.
I think having Sabine and Ahsoka on the Mandalorian would be interesting because they bring different viewpoints to the show. Ahsoka and Sabine could give pointers on training The Child. Sabine could talk about the different Clans and how their rules are different between them.
I thought having a live action show would be hard because their story, looking for Erza Bridger, would be similar to Mando’s story. It could be different if we saw things from Erza’s side too.