Originally, the character of Klaus was going to be a native of France named François. When Dee Bradley Baker auditioned, he told the producers that his French accent wasn't very good, and that he would read the lines in a German accent instead. Producers liked Baker's performance so much, they decided to make Klaus German.
Steve's original design was much geekier and gawky, and he was voiced by Ricky Blitt. Halfway through production, his voice actor changed to Scott Grimes, and his design was made to be more attractive, so he would be less comparable to Neil Goldman from I Griffin (1999). This design is a caricature of series co-creator Mike Barker.
Steve's friend Snot is based on Booger from La rivincita dei nerds (1984) and is voiced by Curtis Armstrong, who played Booger.
Hayley's middle name is "Dreamsmasher."