Something I recently mentioned on OT Radical Redux was deepfaking the original ESB Palpatine onto RotJ Palpatine. I guess there isn’t really enough footage to work with, but it could be acquired through a replica mask.
Since Matt is going to voice Anakin in Lego Star Wars The Skywalker Saga
Is he though? What’s your source? I’d say there’s a 50/50 chance of it going Christensen or more likely an impressionist.