A birth year of 1695-1700 for Sarah (Williams) Cavanaugh, if she was at the end of her childbearing years could be right. Since she married again after Philemon's death and had no more known children, then I think she must have been at the end of her child bearing years.
I would love to be able to figure out if she was the mother of Charles Cavanaugh. Since the name Jael extends down through his line, I keep my finger crossed! Charles only needed to be 21 a the time of his father's will was written!!!