I just heard back from my Johnson family expert and he reports that it was "common knowledge" that Grace who married Peter Johnson was a Hayden that married John Mattingly and then Peter Johnson. He also reports that she was eventually married 5 times - outlasting 5 husbands. He tells me that there is another Johnson family expert and she cites this info in a book that she has written. Her last name is Conner but he couldn't remember much else. I'll keep you up-to-date as I find things.