Actor Allusion: Peko is voiced by Kotono Mitsuishi, AKA Sailor Moon. When she masquerades as Kira Kira-chan, she wears a Magical Girl mask that greatly resembles Sailor Moon and makes a speech about punishing people with justice. Since Mitsuishi was one of the voice actors that the script writer specifically asked for, this was most likely done intentionally.
Fan Nickname: Togami as he appears in this game is known by fans as "Fat Togami" or "Fatgami", due to how...different he looks from when we last saw him. "Twogami" and "2gami" are also popular, given how he's someone completely different from the actual Togami. In Japan, "Tongami" is a very popular nickname for him.
Monobear can be considered one to since his official name is still Monokuma.
Komaeda originally had glasses, and a hoodie with bat ears that eventually became Nanami's.
Nanami greatly resembled Chihiro.
Kuzuryuu's prototype, of a big, muscular man, eventually became Nidai's design proper. Nidai's original was much more standard, with no crazy muscles.
Hanamura was a standard tall and slender Bishounen.
Mikan had shorter hair and more of a Mad Scientist vibe, being covered in stitches (in fact, one sketch has her hand falling off at the wrist) while carrying around a Brain in a Jar.
One of Nidai's early designs was a Long-Haired Pretty Boy. Another was done in the more cartoonish style that was ultimately used for Hanamura, depicting him as a rail-thin teenager with a shaved bald head, oval eyes and buck teeth.
Saionji was supposed to be one of the survivors and Kuzuryuu was the victim of the third chapter in the beta version of the game.