Again, Palpatine was the front, the mask. We don’t know how the history books in the GFFA refer to him. On the flip side of the coin, we don’t even know if Vader’s true identity is widely known.
I doubt we’ll ever see a young Anakin ghost, but a hologram isn’t out of the question.
Vader’s identity is widely known. Everyone knows Luke and Leia are his kids. A First Order sympathizer leaked the information.