I have one:
Every once in a while a character will have 2 voice actors in the same episode/short (kind of hard to explain, but The Amazing World of Gumball episodes "The Kids" and "The Copycats" are two good examples). My suggestion would be a multiple option which can allow us to add additional voice actors to the character. This can also be useful if we wanted to add an voice actor who voiced a character internationally (primarily English actors for dubs of Japanese productions).
For the latter, we would have to do the work of course. We add the country and if we wanted to, note(s) in order to tell the reader this actor voiced this character in the UK while this one voice the same one in the US.
Perhaps maybe this would work better if they were 2 separate options (to avoid confusion).