If I change a Helper layout, will it change where it's used?
No. Helpers are coupled with the page once placed. Changes to the Helper layout will not affect existing instances.
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.
The 'Range' in the menu list item element sets which list items at the current level the settings should apply to.
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.
Yes, this is possible by creating a custom element.