There was a bit of misinterpretation going on regarding something Timothy Zahn said at a con recently. Zahn himself sets the record straight: He has proposals, but not contracts, for two more Thrawn books… And he doesn’t know anything about Episode IX. It’s simply the nature of the franchise that movies will dictate the rest of the content. (And given that Thrawn went MIA in the Rebels finale, and there’s a brand new cartoon coming up… There are a lot of balls in the air even outside of the films that could have an impact on anything else regarding Thrawn.)
Zahn’s next Star Wars book, Thrawn: Alliances, will be out in July.