Various is the correct author for any book with multiple unknown authors, and is acceptable for books with multiple known authors, especially if not all are known or the list is very long (over 50).
If an editor is known, however, Various is not necessary. List the name of the editor as the primary author (with role "editor"). Contributing authors' names follow it.
Note: WorldCat is an excellent resource for finding author information and contents of anthologies.
I had read the French translation from Chamisso's original book as a teenager. This version is quite good. I really liked the illustrations and there are additional informations about Chamisso or related to the story. As well as German exercises, including an online research exercise.