I would question how well the shifters will work with the rear cogs. Dropping between sprockets or off the back might be a problem. Cheap one speed chains are not designed to be shifted.

You have certainly gone to a lot of work on this project. I will stick with my fairly stock Dahon Mu D10 and my Zootr Swift 8 speed with 11-32 rear cogs on both.

I do understand for some people the fiddling with it it is half the fun.

Enjoy