Quoted from Rdoyle1978:
It is exclusively that endorsement may be misconstrued. Voice is not protected by trademark or likeness rights at all. I’ve done tons of soundalike ads and other gigs that bear no risk. Half of voice acting is copying people’s voices in the first place!
Again, these laws can vary by state.
In california for instance, voice IS explicitly named in the right to publicity laws. Specifically:
"(a) Any person who knowingly uses another's name, voice, signature, photograph, or likeness, in any manner, on or in products, merchandise, or goods, or for purposes of advertising or selling, or soliciting purchases of, products, merchandise, goods or services, without such person's prior consent, or, in the case of a minor, the prior consent of his parent or legal guardian, shall be liable for any damages sustained by the person or persons injured as a result thereof."
Generally people tell you to be cautious... as the likeness and risk of confusion leads to risk of liability. https://www.voiceoverxtra.com/article.htm?id=q24we4bv
Just because you've done it and not been challenged doesn't necessarily make it legal. The matter is very much a regional one.
The matter of film characters adds other dimensions as you are typically mimic'ing the character, not a person.. so the likeness is that of the character. The rights the actor has to the character's use and likeness will vary based on their contract... but pretty much since the 80s actors have rights that prevent the studios from requiring them to blanket give away their control.