There are 4 primary phases to how these mannequins will progress in the haunt.
"Normal" = where things seem somewhat normal but the early stages of the haunt are apparent. The mannequins from this point are the ones from when the creator was trying his best to capture the most ideal human forms.
Deconstruction = Where the master having become frustrated with his own sense of inadequacy started to destroy all of his creations violently, perhaps at some point loosing his ability to tell his creations apart from the staff working within his manor and dragging them into the violence.
Experimentation = The point where the creator started adding animalistic features to his creations seeking some new form of inspiration to be his muse, at some point using human bases to speed up the process.
The Arcane = the point were his experimentations with science/magic cross the threshold and give physical form to demonic entities from some other plane of existence. loosing a new form of abomination into the world.
This particular one would come from the deconstruction period. Where more of the haunted/possessed mannequins come from.
Almost finished a second mannequin today, it still needs some cleaning up tho will finish it up tomorrow, a stage 4 abomination. :D