contributors.givenName, contributors.familyName should use facets from author.givenName, and author_familyName.
contributors.givenName, contributors.familyName should be faceted and both of these facets should be combined to be used as the picklist for each givenName and familyName.
contributors.givenName, contributors.familyName should use facets from author.givenName, and author_familyName. contributors.givenName, contributors.familyName should be faceted and both of these facets should be combined to be used as the picklist for each givenName and familyName.