If nothing else, AFAIR, Kobo's firmware treats a comma as a separator for multiple authors. "Jack Green" is a single first name last name author while "Green, Jack" is two authors who have a single name.
Also, keep in mind that Kobo's firmware will sort by the author last name when you display the author list.
As for the collections, the calibre template you are showing has little to do with how collections are configured on your Kobo. See the
Kobo Shelves and Collections wiki entry for some help configuring collections so calibre will manage them on your Kobo.