Hi Cyril,
Indeed, you can choose how your Office 365 calendars and contacts sync to Outlook 2013 by setting up your Office 365 account as an Exchange account or POP/IMAP account. In Outlook 2016 for Mac, you can also set up POP/IMAP account in it to just view email messages. However, when I check the official article about Using POP or IMAP to connect to Office 365 for business account, the information about Outlook 2016 Mac Preview has not updated yet. There can be some other updates on this product. Let’s wait and see!
Best regards,
April Zhou