I just reviewed the thread on the various messages and have a problem with some of the dates that have been posted regarding Grace. One message says she was born 1794 in Chatham, CT and died 26 Feb 1843 in New Durham, Greene, NY and had a daughter Lucy. Then another message says that this same Grace who married Isaac Sears was married November 1780.
This clearly doesn't not compute as she was born AFTER she was married according to the above. Something is mistaken and you can't switch the dates because even if you did, she would have been married at age 14 using the switch method.
Have you found out exactly when she was born? Who her parents are yet?