giant,
i replaced the driveline on my 50 last december. can't recall the numbers for the u-joints at the moment, but i will try to take a look in the morning (when there's light) and see if i can pass any part numbers along.
to be honest, you should be able to go to any reputable drive shaft shop and they should be able to tell you what you need.
as far as the wiring??? sounds like the po's idea of rewiring was just a sales pitch. and the engine turning whether the key is "on" or not is typical if it hasn't been altered too much. the starter engages regardless. the key just supplies juice to the ingnition. when it's in the on position, it should fire.
