You can now both trigger on shared mailboxes and send mail from shared mailboxes. Read more here: https://flow.microsoft.com/blog/canada-mailboxes-aad/
Support for this was added today. Read more here: https://flow.microsoft.com/en-us/blog/search-by-service/
This is now possible with the Get Calendar View action: https://flow.microsoft.com/blog/publishing-and-custom-connectors/