I only have 9 children listed for David E. I don't have John or Mary. I have "proof" via the "Washington Co., Maryland Church Records of the 18th Century 1768-1800" for Christiana, Catherina, David, Rosina, and Jonas. I have proof via Augusta Co., Virginia marriage records for Jacob and Christiana. I have no proof of Leonard, Elizabeth, and Margaret, I just got them from someone elses work. Appearantly, according to the Church records, David and Elizabeth Olinger were not Married at the time of David Jr's birth in 1771. Elizabeth's father is Philip Olinger as he named grandson Jacob Kershner in his will. It is John H. who was Jacob's oldest son.
You said John Martin was your line. Which of his children are you descended from? I am interested in George because I find two different Georges in the Church records during the same period of time, one whose wife was Anna Maria and one whose wife was Eva. Which one is David's brother? Do you know who the other one is?