Leviticus,
Welcome to the forum. I can perhaps help a bit though I haven't tried all of them.
There is no difference between HD and ED glass, it just marketing. Neither are essential for a low chromatic aberration design though it does make the task easier.
The Minox I've only tried briefly at the UK Birdfair and wrote this in my notes:
"The new Minox BL HD I rather liked. It has a appealing simplicity to the design and the mechanicals felt nice and slick. The focus wheel patterning looks better in the flesh than the photos. The FOV was good, CA well behaved, and sharpness about right for the price which looks like it will be just below the Meopro offering. I think they may have dropped the MIG claim on this model, and it feels like a modern Kamakura offering... which I think is a positive."
I've since been corrected and there is a Made in Germany claim, but wouldn't be that unusual for much of the design and production to be done in Japan.
The Zen Rays are a bit of a rarity in the UK but the Hawke Frontier ED and Hawke Sapphire ED are widely thought by members here to be essentially the same as the Z-R EDII and EDIII. Both are very well regarded on the forum, the main difference is the colours and contrast are marginally better in the higher models. I personally thought is was worth the extra but others may not agree. Hawke have a single hinge variant of the Sapphire ED that I prefer. It is a bit more compact and I find it easier in the hand. These all have a wide view and broad sweetspot with a slightly complex field curvature profile and I have noted some distortion in certain situations, but I might be the only one on the forum to report it.
I was fortunate enough to win a ZenRay Prime 10x42 in a forum competition last summer. I am very pleased with mine, much preferring it to the other Hawke (and presumably Z-R) models. It is getting a little heavy but it is well balance and feels lighter in the hand to me than it's cousins. It is a flat view design. Tastes differ, and I prefer flat field in higher powers and curved fields in lower powers. I'd heartily recommend mine but I haven't tried the 8x.
Hope that helps.
David