Add authors without creating authors profile and functionality for all users

Hi,
I have few queries related to the plugin,
1. The functionality for adding co-authors is seemingly working for only admin level users. Is it possible for this functionality to work other user role level?

2. Without creating an author profile can we add a co-author in a post?
Scenario – I have added a new author John with editor role but john is not coming up when searching in the dropdown to add co-authors. John only comes when we create john’s author profile.

Can we skip the above scenario and add any user without creating their author profile.

3. The update button is not getting enabled for a post when adding a co-author or removing a co-author, is it an existing issue or we have to modify something for the button to get enabled after we add/remove an author?