Yes, I am related to Martin though not a direct descendant. I am descended form Martin's brother David who went to Augusta Co., Virginia and ended up in Hawkins Co., Tennessee. I too do not have all the documentation I should have although most of my records are personally researched rather than shared. I have thousands of photocopied pages from books of compiled records most of which don't have any notation as to the name, author, or edition of the book they were from. I have been reseaching my family tree since 1974 when I was a Junior in high school.
My record of the marriage of Martin Kershner to Mrs. Magdalena Ankoney on Jan 19 1804 comes from a newspaper article dated Jan. 25 1804 which states "Married Thurs. last by Rev. Rahauser, Major Martin Kershner, to Mrs. Magdalena Ankoney". I got the 19th as a date from a newspaper on Feb. 1 where an article mentioned someone married on Wednesday the 25th and extrapolated back to the Thursday before the 25th.
Martin and Elizabeth did have a daughter Anna (b. feb. 3, 1790) according to Baptism records of Washington Co., Maryland. Sorry, I did not make notation of minister or church, at the time I was only interested in the birth date.
I also have a newspaperrecord announcing the sale of livestock "at the dwelling house of Magdalena Kershner (formerly Ankoney) near Joseph Fiery's and Henry Ankoney's, on West Conococheague ... Martin Kershner, and Magdalena, his wife".
Martin was executer of his father, John Martin Kershner's, estate. He also seems to to be quite well off according to tax assesment records, deed records, and records of loans made to other members of his family. Tax records for 1783 indicate he owned over 700 acres of land, 11 horses, 10 bc (?)(Cattle?), 2 stills, and 2 Mills. This is far more than any of the other Kershners listed.
As I stated earlier most of my information has come from personal research as opposed to information sharing. Because of this I have quite a few holes in my tree. I know almost nothing on the children of Johann George Kershner other than his son John Martin and his daughter Elizabeth Hager. I find birth (baptism) records in Washington Co., Maryland of children born to Johannes and Elizabeth, Johannes and Anna Maria, George and Anna Maria, George and Eva, Conrath and Hanna, John and Magdalena, and Jacob and Margaretha Angener (unmarried). I also find reference to a John and Anna Maria his wife. Yet I know not where any of them belong for sure. I know Martin had an uncle George and a brother George but which is which I don't know, I only know that the two Georges listed are not the same one by multiple marriages. I don't know whether the two Johannes' are the same person or not. The same is true of the two Johns. All of these birth records are from the 1770's and 1780's. In the tax records fo 1783 I find Martin, David, 2 Georges, 2 Jonathans, a Jacob, and a Philip. Are the two Jonathans the same as the two Johns? What about the two Johannes, isn't John an Americanized version of Johanne. Also I find that various reserchers have Philip listed as being descended from the Berks Co., Pennsylvania Kershners and not the Washington Co., Maryland Kershners. Is this proven or just assumed?
I have listed as the children of Johanne George Kershner as: John Martin Kershner-b.dec 3, 1722 d.dec 1769 Anna Elizabeth (Kershner) Hager-b.mar 25, 1725 d.apr 16 1765 Anna Barbara (Kershner)-b. Jan 26, 1726/27 Johannes Kershner-b.feb 24, 1728/29 d. before 1732 George Kershner-b.ca. 1731 d.1804 Jacob Kershner-b.ca. 1733 d.1776 John Kershner-b.ca. 1740 d.1822 This is from other people's research and is at least 20 or 30 years old. Is it still the accepted information?
I don't know if you have any of these answers or not, but I'm hoping someone out there does.