1. What are the limitations of Save emails to Google Drive?
    The main limitation is that save of labels and continuous save of emails require IMAP to be enabled, and label selected to save needs to have “shown in IMAP” selected. Please check this support note about limitations.
  2. Can extension Save Emails to Google Drive save email messages to Google Team Drive folder?
    Yes – this extension can save emails to any Google Team Drive folder.
  3. Can I save only attachment?
    Yes – you can save only attachments. To do that just Save only attachments in the options dialog:

How to save attachment only