I believe the hub was a "vuelta hub" per this product ad "Aeromax Alloy Wheelset Road Bike Comp 700c" wheelset:
https://www.amazon.com/gp/product/B002XOJD9A/

I could not find any literature on the "vuelta hub" since there are no markings on the hub itself and no hubs listed on their website which I could find, so I found what I thought was the closest match (looks like the same hub per diagram, and it sounds like a shimano). My guess is that it's probably a shimano design licensed and built by Vuelta. Other than not being able to tear it down, it is a pretty high quality hub from what I can tell. Smooth riding.

Solution: no solution. I ended up buying another one of the same wheelset. It is cheap, so it is not a big loss. Sold the old wheels on craigslist to someone who was going to give it a try. I'm not sure if they succeeded or just lived with the rattling / grinding noises. The eight-pound sledge didn't work & that was my limit.

But, yea, a cheap wheel. I think that pretty much sums it up.

mitchmellow62 - if you have another idea how this hub would be attached per the photos here (e.g. https://www.bikeforums.net/g/picture/13206583) I am idly curious as to what the process would be. I agree it feels like it doesn't open this way. Perhaps it's like a2e said... "not reusable". Perhaps glued for a solid, cheap seal.

If anyone can find the Vuelta hub manual, that would be solid, but it's no longer a problem so no worries.

mpetry912 indeed, shimano spoils us. It's probably unreasonable to expect the same level of attention by other brands.

Thanks again guys. Happy holidays.