The reason why all Harkonnen are bald is because the Baron turned bald after he was infected with some disease by Gaius Helen Mohiam after the homosexual Baron violently raped her. Mohiam is the Reverend Mother who tested Paul with the Gom Jabar and she might be Lady Jessica’s mother. Dune is like that. Jessica is definitely the Baron’s daughter and thus Paul claims house Harkonnen after Feyd Rautha, the last heir, is dead.