What units do I add after a value in the Style builder?
You don’t have to add units unless you want to use a specific unit or you’re adding Custom CSS properties.
Acquia Cohesion renames to Site Studio from version 6.2. Tell me more.
No. Site Studio allows the site builder to select, either use of IMCE or Entity browser for browsing and selecting images.
No, the entity browser does not work for component defaults as the entities are content, not config.
Yes, this is possible by creating a custom element.