I know its not the same, but I've had to "map" VR to rectangular walls for tech conferences, and my quick and dirty solution was to stream VR apps over Airplay to an Apple TV, which was piped into Resolume via Blackmagic Intensity 4K. It worked really well, pleasd client and guests alike. Just saying, when pressed for time and budget, you can focus on the overall effect and sometimes come up with simple solutions.
Another idea I played with but never implemented was to just project rectuangular 360-degree footage (with panoramic warping) on the walls and working with the Slide effect plugin. Was thinking an OSC slider could control the position parameter, hence "spinning" the world around you.
With the FFGL plugin, as well as mapping onto a dome (which I hear is tough in Resolume), it sounds like you are pushing for something much more cutting edge. Best of luck, excited to see what comes out!