Your bike should have 2" wheels front and rear. The brake you mention is correct. The other one is a front brake, the guy, bldfla941, just doesn't know any better. He is a local that lives near the Wollard auction, and thought he could make a killing on servi-cycle parts.
As for the magneto parts, if you only need the points, condenser and coils, and not the backing plate, Wayne has those new. If you buy that used one, there is a very good chance that none of those parts are any good.