Definitely think that Ashi survives, but I think her role will be more like a guardian/evangelist of Jack's legacy rather than taking up his sword. Could happen though, we'll see.

The way this season's shaping up, I think we'll get a bittersweet conclusion to the series. My prediction: Jack dies in his final battle with Aku, but his sacrifice frees the world of evil and restores hope for the future.