How HCM Position Hierarchy synchronization works

Summary:

Hello,
We need your input to understand how HCM Position Hierarchy synchronization works.
The customer needs to enable HCM Position Hierarchy synchonization, they want the parent position incumbent to be defaulted in the manager section when hiring an employee. However, they do not want to activate Position synchonization, as some attributes can't be synchronized.

1. Is it possible to enable HCM Position hierarchy synchronization without activating position synchronization on other fields?
   
2. Is it possible to enable Position synchronization only on some fields (departments, job) but not all of them, meaning that if we run the "Synchronize Person Assignments from Position" process other fields like Grade won't be synchronized?