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.
A good book if you want to review the kanji you should know for the JLPT N2. Each chapter has one short dictation exercise and some various other written exercises, and they are short enough that you can do one chapter each day. There's a removable small book with all the kanji you need to know, as well as the readings and examples. It's a fun and effective way to practice.