I guess any one of them might be used if there is an ebook about a movie, an exhibition, a legal case, etc. and if the ebook creator wants to be exhaustive.
I have created some ebooks with illustrations that were originally etchings or engravings, and the etcher or engraver is known (and different from the artist who designed the illustrations), in some cases the illustrations are actually signed by the engraver. I could have added the names is the metadata, but I only added the "illustrator". The fact that I didn't do it doesn't mean that it shouldn't be possible to do it.