A family of Microsoft word processing software products for creating web, email, and print documents.
You put only author names for the relevant chapter in the author field and only editor names in the editor field. If a chapter author is also an editor, the name goes in both fields.
As for adding the a, b, c, etc. suffixes to years, that's going to be problematic. If you don't convert the citation & bibliography entries to static text, the edits will be lost immediately you do anything that causes Word to refresh field codes (e.g. printing the document). The alternative is to add the a, b, c, etc. suffixes to the years in the 'Manage Sources' dialogue itself - which means they'll appear that way in citations and the bibliography alike - but that has implications if you update the master list then want to reference the works in another document but don't reference all of them, since you may end up with unwanted or wrong a, b, c, etc. suffixes there.