@noobtube2 I assume it moreso has to do with the identity they portray to people on the outside. they indefinitely need a face in order to recruit new faces, when the third floor went to get the new batch, they used their "face" rather than appearing as an esteemed shadow-sama. faces gives shadows an identity and personality. but if they can only operate using faces, if their face becomes dissident or have an idea of being independent, obvious that would go against there agenda- humans seem to be disposable and it seems the shadow house pay no mind to manipulating humans.
living dolls is an excuse for their existence, to make themselves less than humans. it could be the reason why only young children are recruited rather than an adult
@Esasaeriri even if it was successful, it would most likely turn out that she cruelly punish to revealing that she got Kate and John involved.