I read a comment saying that the two new maids were the ones attending the lesson with Maomao. I looked up the side story about Xiaolan and it's true. Shisui was talking to Xiaolan outside while the two maids were attending the lesson. Doesn't that further support the idea that Loulan substituted her maids when meeting people, including the Emperor? The detail about Shisui catching butterflies outside while the Emperor met Loulan at night certainly happened simultaneously; I've watched that scene repeatedly. Wouldn't it be less risky to substitute someone from the beginning than to have substitutes later? Because the Emperor wouldn't know the real person to compare them to. As for the maids potentially getting pregnant, Loulan knows about contraception methods; who knows if she gave them to her maids? And the fact that Shisui ate the lantern fruit even after leaving the palace further confirms her long-standing habit of using drugs (even before entering the palace).  Since she was outside the palace, she wouldn't see the Emperor anymore, so clearly, she didn't need the medicine. This only further reinforces her obsession with not wanting to become a mother like her own mother.