A very well-reasoned analysis! I too have been perplexed over the uncertainties about whether William 1 Orcutt had 2 or 3 wives, the second two both named Hannah.
In addition to your Hudson citation, I did find one further (non-internet) reference to the marriage of William (2) to Hannah Newton. It's in a footnote on page 49 of Manning Leonard's "Memorial of Solomon Leonard, 1637, of Bridgewater", 1896, stating that the marriage occurred on April 10, 1706. Charles Hudson's Marlborough history gives the date one year earlier, April 10, 1705.
There is also a Newton-Leonard/Lenard marriage, also in 1705 in Hudson's account: Marcy Newton (sister to Hannah) married Moses Lenard. I see no indication of Leonard's source for that specific date. Nor is there one given in Hudson, to my awareness. This Newton-Leonard/Lenard marriage would show a 2nd Marlboro-Bridgewater connection, which is why the Leonard book is so interesting.
A puzzlement about another matter had me wondering, though, whether William 2's mother may have had some sort of falling-out with this eldest son, whether if so it could have related to another marriage she didn't approve of. Before her 1712 death, she had moved to Weymouth to live with either Andrew 2 or Benjamin 2 and family, where she died. I've wondered why she didn't continue to live in Bridgewater with William 2, which would have been somewhat more typical? Youngest daughter Susannah was still unmarried and living with her in Bridgewater as a minor when William I's estate was divided. William 2 was co-administrator with his mother for his father's estate. That piece of circumstantial-only evidence even led me briefly to speculate whether William 2 had divorced Hannah Smith to marry Hannah Newton, and his mother disapproved! But there is no hint whatsoever of a divorce, or a pre-1705/6 death of Hannah Smith Orcutt. So that episode about why widow Orcutt moved from Bridgewater to Weymouth remains a mystery.
Have you checked land transaction records for the Marlboro area? If by some remote chance William 2 had land interest there, that would buttress the Hannah Newton marriage possibility fairly strongly. The lack of it could be another item to add to your list. Further work could be done in the Leonard family records, following that Leonard/Lenard-Newton marriage Hudson gives.
I recall land transactions in William 2's name from the index of land records at Plymouth during research there some years back (clearly his, not his father's, since they postdated 1693), but unfortunately didn't copy them since I was researching land records for William 1 and Thomas 2 Orcutt. That probably wouldn't be much help, though -- wife's name would be Hannah in either case. (The deed for William 1's May 27, 1670 purchase of the Bridgewater property from Edward Gray of New Plymouth is there -- prompting me to wonder WHY he didn't move there from Marshfield until the early 1680s? That's just to suggest how intriguing information comes from the land records. Also learned from deeds that Thomas 2 Orcutt was married twice -- he, not his son Thomas 3 married 2nd Margaret Ray Sutton -- clear because earlier records listed Jane [Emerson] as his wife, later, Margaret; while Thomas 3's land transactions continue to be with wife Thankful even after Thomas 2 was married to Margaret Ray Sutton. So land records can help with names of wives -- but two Hannahs are a lot harder to sort out!)
William 2 Orcutt's estate administration is somewhat puzzling. Certain specified items go to the unnamed widow (bed and some furniture, 2 pair of sheets, other cloth, including 7 3/4 yards of cloth "which was Procured for a Riding hood for her in her Husband's Life time", and a couple of other items (hard to read). Though the penmanship is difficult to read and blotchy, there seems no indication where she lived after his 1739 death. That doesn't give her the fairly common widow's homestead provision. She inherited no real estate property, so it seems most likely she lived with one of the children. In the administration of William 2's estate, the widow, Benjamin and "Joanna" Edson, Joshua and Jane Warren, Joseph and Deliverence Washburn, Solomon and Martha Washburn, Elizabeth French (husband Ebenezer had died in 1725) all receive property -- Moses Orcutt and Caleb Orcutt "who have received their part" are excepted.
So where did Hannah Smith(/Newton?) Orcutt live after William 2 died? She died in Bridgewater in 1751. If Joanna and Elizabeth are Jane Washburn's daughters as many believe (though the Mayflower Society says they are considered questionable in the line of Francis Cooke, lacking birthdate documentation and clear lineage through Jane Washburn), then the candidates are the remaining five are all possible candidates as Hannah's children (and perhaps Joanna and Elizabeth shouldn't be fully excluded, since some think they too could be Hannah Smith's children). There's no question but what William 2 Orcutt maintained very close ties with the Washburn family well after Jane Washburn Orcutt's death -- his brothers-and-sisters-in-law -- was witness to their wills (always with his mark), and deeds. So perhaps Hannah Smith Orcutt did as well. (And, interestingly, Susannah 2 Orcutt, William 2's youngest sister, married Benjamin Washburn.)
What do you think?
Judy Orcutt Holy