Bad idea, it's a moped not a bike. Would you use moped parts on a motorcycle?
Do search, there was a long thread about derailiur about a month ago.
Long story short, your bike weighs 30 lbs. your moped weighs 120 lbs. You ride your bike keeping an average speed of 12 mph, your moped 20 mph. Shits going to wear out fast or break.
I think the only thing I'd use from a normal bike would be the handle bars or seat. Some downhill bike parts (shocks, hubs, brakes) might be able to take the abuse but they are going to be very pricey.
Do it, prove me wrong, but please be careful.