Honestly I think it would make more sense to introduce her as a new side/main character in the Rebels sequel. If it is a direct sequel to Rebels, following Sabine and Ahsoka’s quest to find Ezra, maybe she could come along on the journey.

Personally I would love a more general post-ROTJ series that brings in vibes of the popular post-Endor EU stories. It could be a perfect way to show the further adventures of Luke, Han and Leia, and their story could converge with that of Ezra, Sabine, Ahsoka and Thrawn.