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.
Yes, the component link field supports both internal and external URLs.
No, the entity browser does not work for component defaults as the entities are content, not config.
Running the composer update command will update any composer packages that have newer versions available.
No site specific data is stored on the API.