Kodinol does not appear in any of my books back to 1941. I don't remember ever having heard of a PAP developer either when I started developing pictures in the 40s or when at Kodak. I would have to assume that it was not sold in the US.

If Rodinal works well with no bromide then that should tell us something about fogging and about development in this developer at this pH with this deveoping agent. Something slightly different is going on than in average developers and I think I am beginning to understand it.

My train of thought does suggest that there are some variants that can be designed with some superior trait or other.