If they are not trying to trick people into believing xyz person did the voice acting, and instead are going for a certain style, I think they would be protected by freedom of expression. Think of how authors of books describe voices in great detail.
i.e. intent matters.
In this case, since the other voice actor has a clearly different voice than SJ, it seems like their intent is to just copy the general 'style' of the voice, and not SJ's voice itself. Speculative though.
