The main characters could be a diverse group. There could be the original inhabitants of the house who had secrets to hide. They might be people from different walks of life, with different backgrounds and interests. Then there could be the investigators or researchers who are trying to piece together the story of the house and its secrets. They would be the ones digging through old records, interviewing people, and trying to make sense of what happened in the house. There could also be characters who are affected by the revelation of the secrets, such as the descendants of the original family or the local community who might have their own opinions and reactions to the secrets being uncovered.
Since it's based on a true story, the main characters might be real - life individuals. It could be the person who first discovered the secrets of the house. Maybe it was a historian, a journalist, or just a curious neighbor. There could also be the family members who were trying to keep the secrets hidden for generations. They might have different personalities and motives for their actions. For example, one family member might be trying to protect the family's reputation, while another might be trying to expose the secrets for personal gain.
I'm not sure as I haven't read or seen it. But they could be the people who lived in the house, like the owners, their family members, or servants who might be involved in the secrets.