According to Ernie Hudson, who played Winston Zeddemore in the Ghostbusters films, he auditioned to voice the character on the cartoon, but the role instead went to Arsenio Hall.
Lorenzo Music first supplied the voice for Peter Venkman who was played by Bill Murray in the films. Reportedly, Murray did not like that his character sounded like Garfield and the producers replaced Music with Dave Coulier. Music did provide the voice of Garfield until his death. Bill Murray later supplied the voice for Garfield in Garfield: The Movie (2004). Bill Murray and Dave Coulier share a birthday together (September 21st).
When auditioning for the role of Egon, Maurice LaMarche was asked not to impersonate Harold Ramis; he did so anyway and still got the part. This led Bill Murray to comment that "Harold's guy sounds like him, I sound like Garfield."
In the early promo artwork for the series, the Peter Venkman character was drawn to look more like Bill Murray and Egon Spengler was drawn to look more like Harold Ramis. But the animators changed the look of Peter, and changed Egon's hair color from brown to blonde, in order to avoid lawsuits for using the actors' likenesses without permission. As for Ray Stanz and Winston Zeddemore, their characters were never drawn to resemble Dan Aykroyd or Ernie Hudson, respectively.
Despite the series being an acclaimed hit on Saturday mornings during its first season, ABC network executives hired a consulting firm called 'Q5' to take over the production department so they could help "fix" the show from season two and onward. Q5, and by proxy ABC, then forced the writing staff and art department to make controversial changes to the series based on their own unstudied ideas in the hopes that the show would appeal to younger audiences. Some of these changes included overhauling characters into entirely different personas, replacing voice actors, removing occult references, re-editing the first season episodes so that they would fall in line with the new Q5 changes, and making Slimer the main character of the series so that his solo spin-off show Slimer! And the Real Ghostbusters (1988) would be better received by children.
These new outlines were so severe and so destructive that story editor and frequent series writer J. Michael Straczynski immediately quit out of protest before the ratings fell to low numbers. And when the ratings did fall, ABC then begged for Straczynski to return to help restore the show to its former prominence while they still tried to keep most of Q5's outlines unchanged. But Straczynski only agreed to return if he could specifically undo the changes that were made to the Janine character and only if the Q5 edicts were kept away entirely from the episodes he would be working on. Yet, despite those demands being agreed to, the show never recovered and was ultimately canceled soon after.
These new outlines were so severe and so destructive that story editor and frequent series writer J. Michael Straczynski immediately quit out of protest before the ratings fell to low numbers. And when the ratings did fall, ABC then begged for Straczynski to return to help restore the show to its former prominence while they still tried to keep most of Q5's outlines unchanged. But Straczynski only agreed to return if he could specifically undo the changes that were made to the Janine character and only if the Q5 edicts were kept away entirely from the episodes he would be working on. Yet, despite those demands being agreed to, the show never recovered and was ultimately canceled soon after.