In this episode it is revealed for the first time that the Cuckoo sisters are working for the newly reformed Hellfire Club.
In the X-Men Comics the Hellfire Club had an Inner Circle of wealthy mutants led by Sebastian Shaw and Emma Frost. They set out to rule the world. The X-Men fought them many times.
The Hellfire Club also made an appearance in X-Men First Class (2011)
The names of Esme's clone sisters are revealed to be Sophie and Phoebe. In the comics, Esme and Sophie are dead, with the other surviving Cuckoos alongside Phoebe being Celeste and Mindee (aka Irma). It was revealed later in season 2 that they did indeed exist however in this continuity they are dead.
Sage states when Sophie and Phoebe were arrested they gave the last name of Cuckoo instead of Frost. In the comics, they were the Cuckoo sisters.
When Sophie, Phoebe, and Esme meet with the mysterious "William" in his office in an attempt to secure their position with the infamous Hellfire Club, they are given a diamond as a peace offering and as funds to continue their mission. It is significant that they are given a diamond because in the comic book Emma Frost, whom the Stepford Cuckoos or "Frost" Sisters (Sophie, Phoebe, and Esme) are clones of, could also transform herself into a diamond in addition to her powerful telepathic abilities.
The location used to represent "Fairburn Vocational Institute" in this episode is actually the opposite side of the very same building used as the exterior of Mutant HQ throughout the first season of the show. Some of the corresponding interior scenes were also shot in that building. (The interior of Mutant HQ, however, is a set on a soundstage).