At one time I, too, assumed that William Rennick and Ann Hamilton were the parents of James Rennick. Later I saw that their son married Elizabeth Yoakum [two databases on RootsWeb.com: Nicoll Family database by Will Nicoll & Bob Juch's Kin by Bob Juch].
The problem, as always, is determining which information is correct. Have you discovered anything further about this?
I am trying to verify the parents of my ancester James Rennick (d Oct 1812, Woodford Co, KY) who married Mary. Their daughter Mary Rennick married Uriah Jones.
BTW, I sent you an e-mail on Apr 13th about my Black/Holman aRe: tors.