The author has confirmed that it's a coincidence that he and Ryan Lee share a given name.
The man in black is an expy of Frankie Black from The Streetfighter's Last Revenge, which like Pretty Cure is a Toei production; the name he uses when disguised, Fredo Black, is a shout-out to Return of the Living Dead (two of whose main protagonists are called Frank and Freddy).
The Cures' transformations and finishing moves follow the standard "Futari wa" formula.
Though "YMCA" is credited to the Village People by Thirteen's intelligence cyborg (and even mentions as much on the monitor), the recording is actually a cover using George Lam's Cantonese translation.
At the start of the episode, Susan is singing "Anataboshi" by MilkyWay from Kirarin Revolution; the lyrics are translated in the English dub, and the title is translated as "When I Come to Your Star with My Love".
Lisa compares her possession to Count Vlad Dracula's ability to turn those he bites into vampires in the final scene of the episode.
During the art museum field trip, Ryan is dressed as the Lilac Fairy, from Sleeping Beauty; Susan is dressed as Princess Florine, from the same production; Rica is dressed as Prince Siegfried, from Swan Lake; Juanita is dressed as a Spanish Hot Chocolate dancer, from The Nutcracker; Tad is dressed as Count Albrecht, from Giselle; and Quent is dressed as Giselle, from the same production.