Thank you for the compliment, I had no welding experience before i started so I'm sure some welders on here would cringe at a closer look. I just wanted to save some money and they looked like fun to ride.
1. That would be a great idea, i never thought about it and didn't even know about reverse threads on the two control rods until after i finished the first trike and read a post on here about left hand threads. If they have it large enough for the axels, i don't see why not. For the axles i had to add threads to the only bolts i could find to tighten them enough.
2. This is out of my wheel house, i just used normal mountain bike disc brakes. (The set is front and back and the holes are different. I didn't realize that and made two the same, and then had to redo the 2nd one.) I added a caliper on the rear wheel because i couldn't find a disc rear wheel, but the next two i used vbrakes and am changing the first to a vbrake. the moped brakes sound interesting, but the mtb brakes have been more than enough to stop quickly, and the vbrake makes powersliding awesome.