If you have watched game theories video on 'sister location' you will understand my theory more. So in the video Mat mentions that there is a timetable in the source code of Scott's page, showing that the animatronics are being rented for events (birthdays, partys, etc.) Now keeping this in mind I believe that the sister location was open at the same time as 'FNaF 4' was based in. In 'FNaF 4' the kid has obvious trauma from his experience at the original establishment. If the hospital he is in had hired the animatronics, the child would have seen them as his mind would have made them seem, big, scary and as if in a nightmare. but it would only be the child's view, the animatronics could have been the versions in 'sister location'. With all this in mind it places 'sister location' in the same time as 'FNaF 4'
but Like gametheory always says, "its just a theory, a game theory"
let me know what you think