The source for David's children is from Forerunners: A History or Genealogy of the Strickler Families Their Kith and Kin, by Harry M. Strickler (Harrisonburg, Virginia: 1925), p. 231:

The Kauffmans.

Mr. Philip M. Kauffman, who with his son, H. M. Kaufman, owns and operates the mill below the White House, in White House Bend (known as the Mauck mill) tells me that his great-grandfather, David Kauffman, married Elizabeth Strickler, daughter of Joseph Strickler of Egypt. His letter is dated April 20, 1914. He showed me David Kaufman's grave in the cemetery near his home, marked with a stone bearing the date, Jul. 15, 1804, indicating the date of his death. He had gathered considerable information which he kindly presented to me, which I here submit in condensed form.

Mr. Kauffman thinks that Nancy Kauffman who married John Strickler of Locust Grove, son of Isaac, was first cousin to his grandfather Daniel Kauffman, and, if his supposition is correct, she was a daughter of John Kauffman who lived at the White House farm. He further states that Daniel's father David lived at the Mill, where he lives now, and that another brother lived above the White House bridge now owned by A. J. Brubaker. He thinks that the other brother was named Martin and the Benj. F. Coffman, of East Rockingham is a descendant.

Material in the last paragraph does not match up to Strickler's genealogy for Nancy Kauffman.

A somewhat different listing for his children can be found in the document, The Descendants of Jacob Kauffman I (from The Brehm/LaPella Family Tree Website).