Im documenting recommended settings for users in terms of licence level, user rights and project level role.
I have created dummy accounts and tried out various operations and have concluded that in general, in a project,
interactors can work with reports, pubishers can publish datasources and workbooks and manipulate self created content. And editors and project leaders can manipulate any datasource/workbook created in the project.
The only discrepancy as i see , is that when it comes to scheduling datasource/workbook only the creator of the data source/workbook can do so. Editors, project leads can delete ,edit &set permissions on the data source/workbook created by another user, but not schedule it or change its schedule.
The creator of a workbook can do anything if the system admins let them. I think it's better practice to only let teh system admins schedule data-source and workbook refreshes otherwise your users coudl cause havoc with your data server and Tableau server performance