Deliberate mistake: After Elsa kicks Bette and Dot off the stage, Elsa looks at the sheet of music on the stand and you see the name of the song 'Criminal' and it also states it's by Fiona Apple which is true, but this season is set in 1952, and Criminal wasn't released until 1996.
Trivia: They pay homage to the original 1932 movie Freaks. In Freaks, Cleopatra gets mutilated and turned into a tarred and feathered bird for visitors to gawk at in terror. Hercules gets viciously attacked under the carnival vehicle. In this episode, Stanley gets cornered by all the freaks under the carnival vehicle and gets viciously attacked and mutilated to resemble Meep (a feathered freak who was killed by the cops in an earlier episode).