If we are to believe that Palpatine was in the plan for the ST all along. Then I guess the “Darth Sidious” name-drop in TLJ was very clever on their part.
and also Palpatine’s voice being heard in TFA as well.
(in Rey’s vision - https://www.youtube.com/watch?v=FATqyG8cGSE & https://www.thisisinsider.com/star-wars-reys-vision-explained-2017-7)
Furthermore, in the throne room scene in TLJ Snoke refers to the Resistance as the Rebels. “I did not expect Skywalker to to be so wise. We will give him and the Jedi Order the death he desires. After the Rebels are gone we will go to the planet and obliterate the entire island.”
Adds fuel to the Snoke being a Palpatine-vessel theory.