I recall reading that one influence on Lorenzo's departure might have been a comment by Bill Murray, who pointed out that Music's voice for Peter was basically the same as Garfield and Bill felt it didn't sound like him.
Which makes it ironic that Murray later voiced Garfield in movies.
Anyway, Murray just made the observation that Venkman sounded like Garfield and didn't mean anything by it, but somebody mistook it for a complaint and fired Music. Which is a shame, since Dave Coulier may have been good at sounding like Bill Murray, but he didn't give anywhere near as interesting a performance as Music had.
It certainly wouldn't be the first time that VAs "borrowed" voices from other works on purpose or unwittingly.
Lorenzo Music pretty much just had the one voice. He wasn't a vocal chameleon like Frank Welker or Maurice LaMarche; nearly all his characters, from Carlton the Doorman to Garfield to Venkman to anyone else, just sounded like Lorenzo Music. Well, except for Venkman's dad, who sounded like Lorenzo Music trying to sound older and more gravelly.
Frank Welker occasionally voiced Blades in S3 of Transformers, and that voice essentially was Ray's, and on one occasion voiced a GB character exactly like Galvatron in TF

.
Most voice actors have a range of standard voices that they use for various characters with minor variations, since there are only so many ways to modulate one's voice. Frank Welker has played so many roles in animation that any given one of his voices has been used for numerous characters. His Ray voice was basically his Fred voice from
Scooby-Doo (his debut voice role, and a role he's still playing more than 50 years later), which is just his own voice but slightly higher and more boyish.
Ernie Hudson auditioned to voice Winston on RGB, but lost the role to Arsenio Hall.
Which was less surprising to me when I heard Hudson's rather mediocre performance as Cyborg in
Super Friends' later seasons, just a year before RGB came out. Hudson's a fine actor, of course, but voice acting is a specialized discipline that live-action performers aren't necessarily good at when they start out. At the time, Arsenio Hall was a more skillful voice actor than Hudson was, although Hudson has improved considerably in that area in the decades since.
But I really liked Hall's work as Winston, as well as the way he was written. In the movies, Winston was the afterthought, the Zeppo of the group. But in the cartoon, he was a full equal to the other three, and he was consistently the most levelheaded and together guy, while able to hold his own in the humor department. Hall's voice work made him a character I really liked and respected.