Thanks so much MattRobertson for your kind and detailed response! Could you tell me if the MOJO chainring you mentioned would fit correctly on the Origin8 crank (I assume it does, or you wouldn't have recommended it!).
I definitely agree that it's the crank to bottom bracket interface where the movement (clicking) is occuring (and I pretty much knew epoxy wouldn't work, but had no other options).
I ride aggressively on hilly trails and weigh 200 lbs, so I'm putting more strain on the cranks than an average rider might., and yes, I've kept them tightened to spec. I'm looking for high quality parts and don't mind the cost.
Final question; I assume that I should replace the bottom bracket and not try to re-use the original in case it's worn a bit. I found this one below. Is it the correct sizing?
Thanks again for your valuable insite!