I may have something to add to this descendancy.
Peter Kleckner/Cleckner of Lafayette, Sussex Co., NJ, died bef. 1800 and among his heirs in his will is "Margaret Coss."For many years I have looked for her husband and where they went (because all Peter's children except the youngest left Sussex by 1800) Her brothers both went to the Union/Northumberland Counties area of PA.
Peter Kleckner is recorded in two wills with individuals I believe to be of this Coss family:
!1769 Feb. 6, Gass, Peter, will of, Sussex County.Son, Peter, horses, cow and plow, to make him equal with my eldest son, George.Youngest daughter Barbary, a cow and a wheel to make her equal with my other daughters.Wife Cattern, rest of estate.Executors:Peter CLICKENER and George Rasor.Witnesses:John Snuke (Snook), Johannis Knoffe, Japheth Byram.Proved March 2, 1769.Inventory made by Coonrod Gontryman and Peter Corcelius.
1771 May 25.Account by Peter CLECKNER and George Razor, Executors of Peter Coss.Catherine Cass, Peter Coss and Barbery Cass were paid their legacies.Lib. 13, p. 552; Lib. 15, p. 104.
!1774Dec. 28Snook, John, will of, Newton, Sussex County.
Wife, Cattern, "benefit of my estate and what remains to be divided among her children that she had before I married her and those since by me".Executors: Son William, Henry Kouse and Peter CLIKENER.Witnesses:Japheth Byram, Peter Space, Christian Slater.Proved 25 Jan. 1775.Inv. 654.19.10.
1776 May 21.Acct by ExecutorsLib. 16, p. 494.
[as an aside, although it's possible the only clerk in Sussex County spelled "Catherine" as "Cattern" consistently, it could also be that the widow in each of these records is the same person, as the widow Snook had children when she married him.]
In addition, I find even earlier links between the Coss and Kleckner families.In the Janeway Account books (store account books from the mid-1700's; the store was near Bound Brook and many people who later went to Sussex Co., were there then), there is this record:
Gause, Peter, Aug 39-Feb 40, a naylor on Lashly's land, brother-in-law to Jacob Lasler
Janeway lists a Johannes Kleckner "on Lashly's land" during that same period and I believe (though unproven) that Johannes was father of Peter.
Finally, I am aware of the profile of Jacob Coss in the Chillicothe paper which names his mother as "Mary Cleckener" but I believe that actually her name was Margaret, not Mary (although they probably would have baptized her as "Maria Margaretha" during that time period.
There was a daughter of Peter Kleckner named Mary who married Widener brothers (one at a time) and moved to Monroe County, New York.I estimate Margaret would have been born ca. 1766-1768, which would make it possible for her to have had her second child in 1788.
This Kleckner/Cleckner family was the only one in northwestern NJ at that time and all Peter's children married into families with familiar Lafayette, Sussex, names:Snook, Flomerfelt, Mains and Weirs.
At one time I added a correction to the Chillicothe profile of Jacob where it names his father as "Jacob" because I believe the name of his father was George but, other than the will for Peter Gass (above) I can't find now why I came to that conclusion - possibly early census records.
I'd be very happy to discuss this descendancy further.