If JediPaxis’ leaked plot descriptions are anything to go off of, I think when Kylo/FO and the Resistance find out Palpatine is alive did change somewhat.
I don’t think Kylo didn’t exactly know what he would find in the Unknown Regions originally. Apparently the info Poe and Finn get from the spy is that Kylo is searching for something in the Unknown Regions, not that Palpatine is alive and has a fleet of warships laying in wait. Leia has a contact that might have a lead regarding the Unknown Regions, and she sends them to Pasana.
It is possible this was not accurate, but I can totally see them deciding to make it clear from the beginning that Palpatine is back in order to make the goals of the characters clearer, and to raise the stakes for the Resistance early on.
I don’t subscribe to the conspiracy theories, but I can totally see the function of the Oracle becoming redundant or contradictory if Act I was restructured a bit. I think Pablo even mentioned on his twitter that Act I received the most changes during reshoots.
Okay, that does make sense. I assumed that the “reshoots” in JediPaxis’ plot summary were just the leakers receiving more accurate info, but it would make sense if Palpatine wasn’t revealed until the end of the first act. Which just makes me want the deleted scenes more, so a fan edit can partially revert the movie to an earlier version, like Hal did in his edit of ROTS.