yo so I was in chillin the other day and I went back to zion after I had finished the dlc already and my companions both just peaced and disapeared somewhere where do they go you guys know?
i dont think they're needed once the dlc is complete.
they either go back to where you originally found them except for raul he goes to his shack just south of the Boomers. Or they go to the Lucky 38 Presidential Suite.
the companions in the honest hearts dlc disappear after they are removed from your party
The DLC companions return to their respected tribes, unless you finished with the DLC completely which the ending explains it all, though they are removed from Zion altogether.