Where we have information on family members, or rough ideas about them, we try to replicate them as accurately as possible given the engine. But where we don't know much about them we either use names of famous individuals alive there at that time or barring that we make family members up as best and appropriately as we can. It varies from faction to faction. Obviously we know more about the Ptolemies in 272 than we do about the Sakae family members in that same year.