Well, Halston himself is obviously a main character. There may also be characters related to his business, like his managers or assistants.
Halston is the central character for sure. Then, there might be other figures in the fashion world such as his rivals, models who worked for him, and important clients. These people would all play roles in the story as it unfolds based on the real - life events related to Halston.
The main character is Halston. In addition, there could be characters from his personal life, perhaps friends or family members who influenced his work or were affected by his career. And also, there may be those in the fashion industry who were part of his journey, like journalists who covered his work, or investors who supported his brand at different stages. All of these would contribute to the complex web of relationships and events that make up the story.