I am a Canadian "Oberholtzer" descendent -- from one of the undocumented lines (not carried down in Barb Ford's Overholser Book - although the line is in the book a couple of generations earlier -- just had to search every Oberholtzer >> Overholt line in Canada to find the right one!).My line generally retained the full spelling -- although enumerators, etc tended to shorten the spelling at random.
Years back I worked with Barbara Ford (via email and snail mail), and we finally put it together. In the process, I also helped her out with the 'Overholt' lines, and sent her copies of the early wills.When she was writing the book, she had an Overholt descendant (who is now in England?) help her with the early Overholts of Lincoln and Welland counties.We found some errors....and lots of 'strays', like your Abraham b. 1819 m. Mary Ecker, etc. Once the errors of the earlier generation are corrected, the parentage of these strays will be solved.
I saw the post of Barbara Ford's passing.She will be sadly missed.