Firestar was created exclusively for the show, however her looks as Angelica Jones were based on Mary Jane Watson from the Spider-Man comics.
Wolverine's appearance in this show has him speak in an Australian accent, voiced by Neil Ross, despite the character being from Canada in the comics. Wolverine also has an Australian accent and again voiced by Ross in Pryde of the X-Men (1989). In the live action X-Men film series that began in 2000, ironically, the character is portrayed by the Australian Hugh Jackman.
Dan Gilvezan initially read for the part of Spider-Man and got the role. After waiting to hear back from NBC, he was told by voice actress Sally Julian that they did the first session last week and that he had been recast. Two weeks later, Gilvezan's agent called and said he was booked to voice Spider-Man because NBC wasn't satisfied with the person they chose after all. All of Spider-Man/Peter Parker's lines in the first episode had to be redone with Gilvezan's voice added in.
The name of the college Peter attended in the Comics, Empire State University, was changed to Eastern State University for the TV series.