Hi folks. Please see my public comment here:
We had a parent for this guy, apparently based on an 1800s source we're now discrediting. Anybody have a better source? Shame to leave him as a dead end, from such a locally-prominent family.
Isaac in California
There's a probate file for a William Cogswell of Chebacco parish (then part of Ipswich) in 1700, with a will. I looked at it briefly, but it's very hard to read and since it's not my line, I didn't dig into it. Might be worth pursuing. It's Essex Co. PR 5865. If you have an AmericanAncestors.org subscription, it's available at https://www.americanancestors.org/DB515/i/13763/5865-co1/245182038
I don't see "The Coggswells in America" in your list of sources. I found him in this book on p.9
There is also a free space page for this book.