Not sure about the fire sticks but the Shield TV’s should work fine for viewing live TV. I know mine works fine. It was part of the first batch of clients to support Live TV. I would suggest using them for now.
How come all other users on my Lifetime plex pass account cannot see the program guide underneth their user names?
Live TV and DVR is current year only available to the admin account. On the Fire Stick question I have steamed Live TV to my TV using the Fire Stick which was using direct play within Plex so virtually no transcoding the mpegts stream was being done on the server.