How about placing a want ad in the online swap meet here?
I could be misreading/misunderstanding what he wants but I think he's looking for vendors for reproduction and rebuilt parts.
As for engine wiring harnesses,
http://www.evanswiring.com/catalog.htmI believe there are other sources for them.
Classic industries shows kick down linkage.
https://www.classicindustries.com/shop/all-years/dodge/all-models/parts/?q=kick%20down%20linkageI'm sure there are other sources reproduction and finding them used shouldn't be a problem.