The Wonderbolts' costumes were designed by Lauren Faust's husband and creator of Powerpuff Girls (1998), Craig McCracken.
Andrea Libman does Fluttershy's singing voice, but not Pinkie Pie's. She stated the reason is because Pinkie Pie's high pitched voice tends to be a strain and that singing with it really hurts her throat. The singing voice actress for Pinkie Pie is Shannon Chan-Kent. Andrea made an exception to not singing as Pinkie at the MLP Fair and Convention on June 25, 2015, when she sang for a fan's birthday, and a Netflix exclusive short where she and Pinkie Pie sing Happy Birthday.
One regular background character pony with an hourglass cutie mark was noted by fans to have a distinctive resemblance to David Tennant's version of The Doctor of the British TV series, Doctor Who (2005). As such, he has taken on the fan nickname, Doctor Whooves, and is the subject of numerous fan creations, although his official name in the series is Time Turner. However, Hasbro has released an official figure of the character under the name Dr. Whooves with a collar and tie to accentuate the resemblance to the 10th Doctor. In addition, he appears in at least one variant cover of the official My Little Pony comic book with numerous references to the British series.
Lauren Faust originally wanted to call the villain Nightmare Moon; Discord. But executives from Hasbro decided the name would be too confusing for their target demographic to comprehend. However when pitching for the second season premiere, Hasbro execs had no problem with the name when Executive Producer Lauren Faust mentioned the character was akin to Q from Raumschiff Enterprise: Das nächste Jahrhundert (1987) The comparison led to show producers actively seeking out John de Lancie to voice the character.
The background character Sweetie Drops (also known as Bon Bon) almost always uses a different voice actress every time she has a speaking role for her appearances.