Acquia Cohesion renames to Site Studio from version 6.2. Tell me more.
Yes, you can use Drupal fields in certain parts of Acquia Cohesion.
It depends on the use case. For fields and their field formatters use a 'Field' element, for data without field formatters, use a token.
The style preview may not be updated because the refresh icon hasn't been toggled to the active state.
Running the composer update command will update any composer packages that have newer versions available.