My wife is a descendent of a William Israel Porter (1839-1876)who resided in Washington Co., IA. I have Alton, Mo. as his place of death, so it sounds like a possible connection (is Alton in Livingston Co.?). He had a son (my wife's grandfather) named James David Porter (1874-1940) and daughters Lyde and Kate. I am not sure if he had siblings.
I am fairly certain that William Israel Porter's father was John who was a "Pioneer from Ohio, and founder of River Junction, Iowa."
I would be very interested in any further pieces you may have.