Interview from a few weeks back.
I think it was first posted in the speculation thread but couldn’t find.
Q:Will you work with Nolan again on a long-feature?
HZ:God knows! I mean I spoke to Chris a few months ago and I asked: "How is it going?" And he said "I’m sitting in front of a white piece of paper" so... [laughs] I understand that.
Q: Can you tell us what you’re working on at the moment?
HZ:I’m working on a movie right now, I’m not telling you the name of it, but I just looked on my Ipad where I keep all of my ideas etc, and I’ve got over seven hours of music, just for this one movie. And we will use something like two hours. And the rest will all be thrown away. But it’s ok. It’s all part of the process.
Chances are he was referring to Dune with the movie he wouldn’t name(This was before he was announced).
Ramin and Lorne have both written for Nolan films before, so they’re interesting safeties. I just can’t imagine Zimmer prioritizing another film or director over Nolan. So if Zimmer isn’t back, I would argue it’s because the Zimmer sound isn’t appropriate, and Nolan isnt going to hire one of his protégés.
Does seem like it would be a slap in the face. Probably would need to be someone on the complete opposite end of the spectrum. Although, I feel like Nolan would push Zimmer out of his comfort zone anyway. That is kind of their thing.
By the way, there is a possibility that Zimmer might still be involved even if he's unable to do it himself due to his busy schedule. He could collaborate with someone from his team. Lorne Balfe, Benjamin Wallfisch, etc... and make it officially a co-composer kind of thing.
He made BR2049 with Wallfisch while he was on tour. Wallfisch did the bulk of the score while Zimmer worked on it as much as he could and supervised the whole thing.
One more thing... I don't think this would be a "divorce" of some sort Nolan might not have approached Zimmer soon enough and he has obligations towards the studios and directors. It's not like he chose to work on those movies over Chris'. And what with the "Zimmer's style might not be appropriate". He's a legend and can write anything at this point.