Here I go writing a follow up on this thread, in case anybody cares, and to then ask a few Leap Motion questions…
So, I ended up contacting customer support, which took care of my issue with great expediency. That was nice!
Afterwards, though, I asked whether we might see the store return at any time - whether they had any news I might share here, and got in response only the exact same cut and paste text as last time, about maintanence and contacting customer support, along with a link back to this very thread, which I had myself started… 
I guess we might as well think of the backer store as gone forever…
…but I’ve got my hand tracking module now! …and would like to ask a few questions of more experienced owners… :7
Am I missing something in the Leap Motion control panel, for aligning the Leap tracking space with real-life and virtual world space, maybe by holding onto one’s controllers and moving them around in front of the Leap cameras?
The latency is extremely off-putting, and tracking is quickly lost when the cameras can not see all fingers simultaneously and well separated, which unfortunately includes pointing at something in front of me (given that’s away from the cameras), but I could probably live with these matters for many situations, if my virtual hands could at least be in the same place as my real ones, instead of varying decimetres off…
This is most likely entirely unrelated, but a few minutes into my playing around barehanded in the Pimax Experience (impossible to point at anything - tracking ambiguity makes the pointing finger wobble and crook), my view suddenly “split” – kind of like when you are using an application that needs parallel projections without it, except it is not that… It happens everywhere, regardless of pp/fov settings, and reduces the stereo overlap as well. The view is now pillarboxed (per-eye views possibly shifted out laterally), with black boxes, but when this first happened, the pillarboxes were filled with duplicates of the rendered views.
I’ve tried some rebooting, and flashing the latest firmware, but this does not seem to have any effect.
I am pretty sure I have seen this issue discussed here before, recently, but can only seem to find threads an on a similar, but different issue.