It's a manufacturer specific bearing unfortunately... As said, the Try-All ones are the same.
I *think* (from memory) one of the larger sizes is a .5 too.
It's Ti-N coated (Titanium Nitride) - the same stuff they use on parts that are designed to have good wear resistance... ie. be very slippery! I know someone who had one and it just refused to work unfortunately.
For batch production, there's no way they wouldn't use a jig, it would be way too slow. The weld distorts in cooling and heat treating, which could throw mounts off a little theoretically.
Cost - having 2x 20" wheels is the cheapest way to make an entry level bike. Many customers already say that £349 is quite a lot for an entry level bike, so if they have to spent over £400 it would make the sport look very difficult to get into.
ACTUAL flange diameter is of no use/consequence really. If you put PCD then I think it would confuse people, but yes, anally (engineeringy? ) speaking it is 'hub flange PCD'.