Acquia Cohesion renames to Site Studio from version 6.2. Tell me more.
Base styles are CSS styles for HTML elements.
No. Helpers are coupled with the page once placed. Changes to the Helper layout will not affect existing instances.
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.
You can style tables or forms through the use of base or custom styles.