It's a mix. The core of the story has roots in truth, but for the sake of entertainment and storytelling, certain aspects could be embellished or adapted.
It's most probably not a true story. Usually, such works draw from a combination of fictional concepts and maybe some loosely inspired events or themes, but not a direct account of reality.
It is indeed a true story. The book and subsequent adaptations draw from factual accounts and real-life circumstances to present a compelling narrative.
I'm not entirely sure without having read it specifically, but likely there are characters who are part of the religious community that the story focuses on. Maybe there are religious leaders or devout followers who play significant roles.
I'm not sure exactly as I don't have full details about this story. But it could be religious leaders or ordinary people within the context of the story.