One main theme is likely to be survival. The daughters had to survive in a very oppressive and often dangerous cult environment. Another theme could be identity. They would have to rediscover their true identities outside of the cult's imposed identities.
Well, 'Daughters of the Cult True Story' might be about the experiences of women who grew up in cults. These women often face various forms of abuse, indoctrination, and control. They may have to struggle to break free from the cult's grip and then deal with the aftermath of their time in the cult, like rebuilding their lives, dealing with trauma, and reconnecting with the outside world.
It depends on how you define a true story. 'Four Daughters' might have elements drawn from real life, but it could also have fictionalized parts for dramatic effect.
No, 'Fathers and Daughters' is a fictional tale. It might draw inspiration from real-life emotions and relationships, but the specific events and characters are made up.