I reinstalled my whole Oculus app stack which then required me to re-sign into the Facebook account, but the same issue occurs. The support ticket is ongoing. I'll try unblinking and re-linking it again and see if it works.

No worries, I may have misunderstood your original requirement. Did you want to live-stream a 360/180 video and watch it live in the Gear VR headset, or did you just want to watch a normal flat 2d video? If you're looking to do flat video, as I menti...

Enable developer mode and turn on secondary display (720p secure) then install Google Home and Cast screen to your Chromecast, then put the phone in the Gear VR and proceed as per normal.

There is a game I've just tested called Swords in Space which has directional tracking on the sword - you can move it left or right, or do figure eights with it. So it's definitely possible - might want to contact the developer of that game and see h...