Editing Permissions in PublishPress Authors
This guide has useful information about controlling the editing permissions in the PublishPress Authors plugin.
By default, PublishPress Authors follows all the standard rules for WordPress permissions. If someone has permission to edit a post before PublishPress is installed, they will still have the permissions after installation.
Permissions and Guest Authors
If a WordPress user is selected to be one of the authors of a post, they will have the permissions to edit that post.