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, you cannot layout forms with Acquia Cohesion.
You can style tables or forms through the use of base or custom styles.
Running the composer update command will update any composer packages that have newer versions available.
Yes, this is possible by creating a custom element.