So, if you want to follow the original FNAF lore, than these are machines that are called Animatronics, but have a soul trapped inside of them, that are cursed to be stuck inside these machine-bodies.
However, I don't know if the devs made this cannon, since this is just a parody of the actual game.
The secrets, are codes you enter into the custom night settings, which allow you to get plushies (easter eggs), and sex scenes. Some codes I know are: 6969, 1987, and default 8008.