As I'm not acquainted with this novel, I can't name the main characters. But typically in such a story, there would be a central character who has the goal of becoming a star. This character might be an outsider at first, someone who doesn't fit the normal mold of a star - to - be. There could also be some side characters who are either supportive or obstructive. For example, a loyal friend who helps the protagonist through tough times in the industry, or a jealous competitor who tries to bring them down.
Since I haven't read the book, I can't tell you the exact main characters. However, in a story about making a star, there could be a main character who is a young and ambitious person. Maybe there's a mentor figure, an experienced star or manager who guides them. And of course, there would probably be rivals, those who are also vying for the same opportunities in the star - making world.