The K-Pop Demon Hunter color palette and the catchphrase, "For the fans!" makes their inclusion feel like a no-brainer. Assuming Universal can secure the rights. Some sort of concert show would melt Guest's faces off.
Maybe it is too early to speculate but I did see someone online share that they felt the Forbidden Forest venue would be a perfect spot to hold some sort of E.T. encounter and I liked that idea. It would be a little weird to queue up in Hogwarts so if they wanted to stay thematic they could switch the entrance/exit order and use that long walkway between Potter and the Studio Tour as queue space but this is all just spitting ideas out. I am looking forward to what they cook up for next year.