We're not talking about the same type of immersion. One can be immersed in a story and one can be immersed in a setting/environment. Those are not the same thing, though they are not necessarily mutually exclusive. See Vincent LaForet's thoughts on the 48FPS "Hobbit" - it's a great example of the dichotomy.
Yawn. Everyone in VR is making films with spatial audio using ambisonic microphones. The ultimate immersive experience of spatial audio is one that tracks and moves with your head and is binaural encoded so it sounds like it's right at your ear, not a stationary one heard while sitting in a theater with speakers many feet away. This film seems like it couldn't figure out which tech generation it wanted to be in and is just gonna get lost in the transition from film to VR (like radio to TV). It chose the wrong medium for better immersion.
Few notes: The light-field camera you were looking for was the Lytro Immerge. You also don't want to "shake the rig" for motion sync - just do a simple rotational twist along the X-axis (it's never not worked for me). Also "A green screen can also be used to stitch the foreground and background separately"... do you mean compositing? Finally, "Use professional cameras. GoPros are fun and small and easy to get, but they’re also potential points of failure and not as reliable as more pro cameras." Yeah, good luck getting a more "professional" stereoscopic 360 camera that doesn't rely on GoPros and isn't proprietary. The Nokia OZO is supposed to be a mess and, at this point, is a waste of 60k as it will be instantly outdated. GoPros aren't great, but it also sounds like a you jumped the gun by doing a very hard project as one of your first - people should get comfortable with mono before going stereo.
Most of the sickness would be from a lack of stabilization and keeping the horizon line at the center. It's kinda strange that they didn't. Stabilization of 360 video is actually very easy with no quality loss when you do it in a program that understands 360 space like Autopano - though I'm not sure how I would do it outside of that program (and maybe that's why they didn't stabilize).
VanWeddings, were you watching with Cardboard/GearVR/Oculus or just on a naked phone/computer screen?
Tilman, was there a source for that? VRSE generally uses it's own custom, self-made VR rigs. They only use Google's Cardboard for distribution.