Begin the film with a prologue of Scar and Mufasa in their younger days to show Zira’s relationship to Scar, cut to the present with Zira on the outskirts with Kovu. The thing is, they could probably show anything the prequel might tell at the same time as telling the present day story. I do expect, however, Hans Zimmer to be asked to score the sequel. I was hoping that after Beyonce's song was snubbed at the Oscars, Disney would come to appreciate talented and experienced songwriters, but I doubt they learned the right lesson from that experience. They were allowed to write only two new songs, one of which was cut and the other relegated to the end credits and they weren't allowed to work on the new arrangements and recordings of the old songs. They were essentially locked out of the filmmaking process. Disney barely made any use of them on the first one. If they are asked, they will have no problem to return as The Lion King property means so much to both of them, but I highly doubt they will be. Whether this sequel is or isn't a musical, I don't expect Disney to invite Elton John and Tim Rice back. If they want to tell the origin story of Mufasa and Scar, they should do an outright prequel. I don't like the back-and-forth structure of the sequel. It's possible audiences will reject this if it's something radically different from what they know, like they did Mulan.
These remakes are successful only because they capitalize on nostalgia. People won't easily accept a brand-new story. People want something that's familiar to them and the animated sequel is actually pretty beloved by audiences and generally considered one of the best DTV sequels. So, this isn't going to be based on The Lion King II: Simba's Pride? Big mistake, if that's the case.