Do I have to use IMCE?
No. Acquia Cohesion allows the site builder to select, either use of IMCE or Entity browser for browsing and selecting images.
Acquia Cohesion renames to Site Studio from version 6.2. Tell me more.
No, there is no way to roll back an Acquia Cohesion package import.
With Acquia Cohesion Sync you can export Acquia Cohesion configuration in full or in part as a package that can be imported into a different website.
An Acquia Cohesion Package file is a .yml file that contains Acquia Cohesion Configuration. The package file allows you to import and export between environments.