Skip-tooth chains are pretty cheap here. Under $50 as these chains were very common on US heavyweights. A cog may be a bit more tricky as it needs to be compatible with the hub, but those can be under $20.

The Copake auction site would be a great place to look for handlebars.

http://www.copakeauction.com/

Good luck with your project. Looks to be a fun one.