the previous owner had the animatronics suited as an old generation so their circuits and thinking power weren't the best when it comes to the night. Pinkie and the previous owner were best friends until he went missing and on his will he said that he leaves everything to her. so all pinkie had to do is make the costumes for them.
She only made 4 because the previous owners already had 5 animatronics endoskeleton (aka robots) made. This place is a party for all Fillies and Colts to enjoy and have a great time playing and singing with the animatronics Pinkie Pie made based on her friends.
