Xfinity Email Folders out of sync with Outlook

I have been using Outlook to manage my emails for years. I am currently using Outlook as part of MS Office 2013 ... obviously out-of-date, but that is another story! The good news is that I am able to receive NEW email in Outlook. In fact, my Inbox on Xfinity is in agreement with my Inbox on Outlook. The problem is that not all folders in Xfinity Email are in sync with Outlook. I would like to get my email in-sync so I can migrate to Thunderbird. 

Over time, I have used Outlook to add and delete email, and have also updated folders (added, deleted, renamed, moved, etc.). The odd thing is that some changes made in Outlook are reflected in Xfinity Email but others are not. One of my primary frustrations is that folders that have been deleted in Outlook are not deleted in Xfinity. In addition, some folders that have been deleted in Outlook are grayed out in Xfinity. Another core issue is that some folders added (or moved) in Outlook are nowhere to be found in Xfinity Mail.

Xfinity Email settings have all boxes checked, including access through third-party programs such as Outlook. 

Outlook Account Settings show Account Type: IMAP; Incoming mail server: imap.comcast.net; Outgoing mail server: smtp.comcast.net. 

Thanks in advance for your help in getting my Outlook in-sync with Xfinity Mail in preparation for migration to Thunderbird.