Perhaps the Star Forge will more likely to appear than the Eclipse. The Eclipse were based from "Shadows of the Empire" comic book series I believe.
Star Forge would be nice since it would rationally explain how the FO was able to a mass so many ships in so little time and it would give Disney a bridge into movies/shows related to KOTOR.
Eclipse will appear because it was canonized in Aftermath: Empires End. Sloane and the Sr and Jr Hux discovered it in the Unknown Regions after the Battle of Jakku. There’s no way it’s been sitting around doing nothing.
Spoiler Warning here....
My theory for IX is Hux will somehow mutiny and take control of the FO from Kylo and command it. Take out most of the Resistance including Leia. And because Kylo and Rey both seem to have feelings for Leia they’ll somehow have to work together to take out Hux and end the FO. Then make Reylo babies and episode X, XI, XII will be based on Relyo Skywalkers.