Part 2 will need Feyd and The Emperor, who wasn't in part 1 either. The Baron doesn't have an heir, Feyd is his nephew and chosen heir. They need to have a Harkonen foil to Paul for the second movie, I just don't see Bautista's Raban being combined with Feyd into a single character. The Baron has the beast serve as his enforcer, he's not someone being groomed for political leadership like Feyd is. The second movie will have to be about Paul's ascendance while The Baron is also trying to secure his own legacy. Part 1 has a monster cast, I have no reason to think they wouldn't swing for the fences when casting Feyd and The Emperor as well.