I think the circumstances you mention - that James Ireson was in the right place at the right time and Jacob named a son James Ireson McNeil - are pretty good evidence that James was the father of Jacob. Do you happen to know who Jacob's mother was? Also, what was "the right place at the right time" in this case? It had to be where Jacob was at one time.
Yes, I would appreciate very much your sending me the McNeil information.
My McNeil in-laws live in Roanoke. They came there from nearby Floyd County. Perhaps you are related to them.