I found something on a Lafferty family in Highland Co. in the Elsie Johnson Ayres book, Highland Pioneer Sketches, etc. Briefly...

"Mary Sprinkle, born 1820, became the wife of Wesley Lafferty. Born in 1820, he was the eldest son of James Lafferty, a shoemaker of West Union in Adams Co. The other children of James Lafferty and his wife, the former Mary Synder, were John, Absalom, Rebecca, Elijah, Amanda, William and Quincy Lafferty. Quincy, youngest in the family, was only ten years old when his father died in 1841."

There is more, including a list of Wesley and Mary (Sprinkle) Lafferty's other children: Samuel, Henry W., Eliza, Lydia, Lieuphenia, and Clara. There is also a reference to Elijah Lafferty's store and shop which later was known as the Honolulu Post Office. This was in the section of the book about Salem Township.

I did not see any direct reference to your James Lafferty, but I suspect he very probably came from this family, especially since James appears to be the name of one of the elder members of the family. I see there is a James Lafferty who is about the right age to be your James living in the 1850 census in Salem Twp, Highland Co., with parents William and Maria. Very likely this is the William who was a son of James Lafferty the shoemaker described above.

There are also some references to a Brown family in Clay Township (there was a Brown's tavern there) including one or two James Browns, but neither of them appear to have a wife named Cynthia (their wives were Rebecca and Margaret.)

Ayres doesn't list any Stillwells in her index. There are some references in the index of Ayres' other book, Hills of Highland, to members of the Lafferty family but I didn't see any James references in that one.

If any of these sound like they might be what you're looking for I can scan the pages for you.

Don