Your basic analysis-that the Joseph born in 1775 is not the Joseph who married in 1781-certainly seems incontrovertible!What is the source for Joseph's (son of Christopher and Molly) birth date?
In your fourth paragraph, you refer to "vital records" and "vital record cards."Are you referring to the vital record cards in the vault in Concord, the New Castle vital records or the cards at the New Castle library (or a combination of all)?
Some time (presumably after I retire), I would love to spend a few weeks in New Hampshire trying to make some sense of the Amazeens.As you say, there are too many Josephs (and Ephraims, not to mention Benjamins, Christophers, Henrys, Johns and Williams).
In any event, thanks for all your information and help.