Project time entries and project expenses

Summary:

I understand Oracle Cloud has functionalities to restrict project time entries by team members in OTL. I will be interested to understand if this functionality is all or nothing....?

Similarly does Oracle Cloud have a functionality to restrict project expense reports by team members? or any other means we can achieve this?

Additionally, is it possible to allow all employees in a business unit to book time entries and expenses in their home business unit [lets say BU1] whilst only selected employees in other business unit's [BU2, BU3] can cross charge to time and expenses to projects residing in BU1?