They would have to either recast Finn or do something animated.
Pretty sure John Boyega doesn't want to be involved with Star Wars anymore...
I think if he sees the people in charge care about making a good product he would do it. You would probably have to offer him some sort of creative control.
Im going to say Darth Vader,hes the only person in Stars Wars I actually care about after discovering him recently
I mustve watched something that made start getting youtube suggestions of his comics. I watched a few videos and kept watching. I know hes a villian,but at least in these comics he actually comes off kinda hilarious and petty at times
I watched one where somebody was about to beat the record he set as a kid in a race. So he used the force to make the vehichle crash before they could break it
Vader wouldnt need to be the main character. It would mostly be people telling their stories about how they survived Vader. Fought with Vader. How Vader saved their lives. So you would be getting both perspectives. From people who love and hate Vader. Vaders not even on that much because its mostly being told as flashbacks,or people talking in the aftermath about Vader