The following is an excerpt from my file on the Haines family, in which the issues you mentioned are raised.
233. ROBERT HAINES
Robert Haines b. ca. 1774, d. Douglas Parish, York Co., NB ca. 1851, m. Amy Gallop, d/o Nathaniel and Hannah (Parent) Gallop.
That Amy had as her maiden name, Allen, and that she was a d/o Peter and Dorcas (Gallop) Allen; seems a matter of doubt. In response to a posting (New Brunswick GenForum, # 3328, 18FEB2006) by Tim Cooper, I wrote, in part (# 3329, 18FEB2006):
In this is mentioned Amy Allen, d/o Peter and ‘Dorcus’ Allen, who m. Robert Haines, s/o Joseph and Elizabeth (Saunders) Haines. Your posting seems to suggest that Dorcas’ maiden-name was Gallop, and that it was her sister who m. a Haines. There seems a contradiction between the two points-of-view. Robert Haines is given as b. Maugerville, Sunbury Co., NB ca. 1774. While the date may be close, the location is impossible as the Haines’ came to NB in 1783. More reasonable is the data for Robert's brother, Peter Haines b. Rye, Westchester Co., NY 16JAN1772. Rye is more likely as a place-of-birth. The third brother, Joseph Haines III is given as b. Maugerville 1783. Possible, but, in light of the above, suspect.
The first point is that, even in the most complete compilation, the information is suspect. The second point is that; if the Dorcas, wife of Peter Allen, above, was Dorcas Gallop, and a sister of the unknown Gallop who m. a Haines, then it would seem that you should be looking one generation back for Haines, or one generation later for Gallop. I must admit that either case seems unlikely and I am at a loss to resolve the conflict.
The next question is, which Nathaniel Gallop are you referring to? There were:
Nathaniel Gallop (1707-1744) m. Dorcas Collins; had a daughter, Dorcas. who m. Solomon Nash.
Nathaniel Gallop (ca. 1734-) m. 1st Hannah Parent; m. 2nd Deborah (Newcomb) Miller; widow of Isaac Miller; had a daughter, Dorcas b. 28FEB1774. (That Deborah was, in fact, Deborah Newcomb, widow of Isaac Miller, is theoretical but based on good, circumstantial evidence.)
Nathaniel Gallop (1771-1851) m. 4JAN1797 Elizabeth Clarke. Elizabeth Clarke may be the Elizabeth Gallop b. ca. 1776 in Kingsclear Parish, York Co., NB in 1851, with children: Charles (ca. 1818), Lydia (ca. 1809), Ruth (ca. 1812), Thomas (ca. 1820) and Esther (ca. 1823.)
Nathaniel Gallop (1801-1891)
Peter Allen seems to be the same given as b. ca. 1762 (or 1752), m. 20JAN1819 (?) (wife's name not given.) A compilation on Peter and Dorcas' family is at:
An interesting feature of this compilation is that, while it confirms your assumption of a strong alliance between the Haines and Allen families, it does not include Amy Allen, wife of Robert Haines. In fact, if the dates for Peter and Dorcas’ children are accurate; then it seems unlikely that Amy was their daughter.
If Dorcas, wife of Peter Allen, was the sister of the daughter of Nathaniel Gallop, and if Peter Allen was b. ca. 1762/3 (which seems more likely), then Dorcas is likely the d/o Nathaniel and Hannah (Parent) Gallop; that is, the Dorcas b. 28FEB1774. Compilations on the Gallop family fail to note whether she was married. An example is at:
http://www.onelibrary.com/Genealogy/gallop/pafg01.htmhttp://www.onelibrary.com/Genealogy/gallop/pafg01.htm" l "2298
Here, there is no sister, Sarah; and other sisters are:
Hannah Gallop m. Edward Burpee
Mary Gallop m. Solomon Farley
Lydia Gallop m. 1JUL1802 Daniel Jewett
On the other hand, (and this appears to be your source), a note at:
“Gallupe-Farley answer to a query, BOSTON EVENING TRANSCRIPT; 1780-1905; dtd 3 Jan 1935; #346; MN Hist Soc, St Paul (Rick Crume's file #G 502, G 510); NOTE: (Nathaniel?) Gallupe had eight daughters & three sons. The daughters married Edward Burpee, Thomas Burpee, Solomon Farley of Boston, Isaac Miller of Southampton (York Co, NB), Mr. Jeweth of Mak-Mageak (Macinquae), Mr. Allen, Mr. Harris and Mr. Hanes, the last three all of Keswick (York Co, NB). The sons were Benjamin who settled on the opposite side of the river near Burpee's Bar, Benjamine opposite Hartland and Samuel at Wicklow. Apparently either the name Benjamin or Benjamine should have been recorded as Nathaniel.”
This appears to have been a rather garbled memory. At least it supports the concept that Dorcas Gallop b. 28FEB1774 was the wife of Peter Allen. It follows, then, that “Mr. Hanes” was likely b. roughly 1760-1775. Also, that "Mr. Hanes" was of Keswick suggests the Haines family. It also suggests a son of Joseph Haines II. The three known sons of Joseph are:
Peter Haines b. 16JAN1772, m. Elizabeth Estey
Robert Haines b. ca. 1774, m. Amy Allen
Joseph Haines III b. 1783, m. Nancy Anne Boone
An interesting feature of the note, mentioned above, is that it suggests that Nathaniel Gallop had 11 children; 3 sons and 8 daughters. The compilation before that lists only 3 sons and 6 daughters. That is, 2 daughters appear to be missing.(Nathaniel Gallop had 7 children in 1783.) George Havelock Flewelling (my not too distant cousin), in his compilation of his own ancestors, notes that Peter Haines m. Elizabeth Estey 24NOV1795. Internal clues in George's work suggest that his information came from a family Bible, and is likely accurate. Joseph Haines III and Nancy Ann Boone are my own ancestors. Amongst other things, his father's will (Joseph II’s, made 1827) confirms only three sons, and mentions ‘Nancy Boone alis [sic] Hains Wife of my said third son’. I am convinced that Joseph III's wife was not a Gallop. Fairly reliable information suggests that if a daughter of Nathaniel Gallop m. a Haines, then it must have been Robert Haines. As above, it appears that Robert’s wife, Amy, was not (as given) a daughter of Peter and Dorcas Allen. This raises the conjecture: ‘What if some document mentioned a relationship between the wife of Peter Allen and of Robert Haines, and it was assumed the latter was the daughter of the former?’
Another daughter not contained in the Gallop compilation, but mentioned in the note, was the wife of 'Mr. Harris', whom you name as Sarah. Her husband you give as Samuel Harris.
The IGI gives Robert Haines as m. 24NOV1795 (but not to whom.) Note that this is the same date as Peter Haines' marriage. Two possibilities exist; either Peter’s marriage date has been incorrectly assigned to Robert, or it was a double wedding.
The impression I get, confusing as the information is, is that Amy, wife of Robert Haines, could not be a daughter of Peter and Dorcas Allen; and that Amy might be the ‘missing’ daughter of Nathaniel Gallop.
Such a hint of a relationship is in the marriage of David Albright to Hannah Allen 10DEC1818. Witnesses were Robert Hains and Isaac Allen. All were of Queensbury Parish. Hannah (b. ca. 1792) is also given as a d/o Peter and Dorcas (Gallop) Allen; and would appear to be Robert Haines’ sister-in-law; but I believe his wife was Hannah’s aunt.
While not conclusive, it appears possible that Amy, Peter’s wife, should be Amy Gallop, d/o Nathaniel and Hannah (Parent) Gallop.
Added to the above is that George Whitman (or Robert George) Haines  b. Burtt’s Corner, York Co., NB 17JUN1803, d. 6OCT1858/9 (will made 1853, probated York Co. 1858?), bur. Scotch Settlement Cem., York Co., NB, m. 17JUN1820 (7JUL1824) Amy Anna Allen (b. ca. 1802), d/o Peter and Dorcas Allen. Again, there is some confusion, especially about his name. However, if he was, for example, Robert George Whitman (or Wightman) Haines, it is possible he was confused with Robert Haines. At least his wife, Amy, seems more likely a daughter of Peter and Dorcas Allen than Robert’s wife.
Dorcas, widow of Peter Allen, is said to have stated in an 1842 claim for a pension as a widow of a soldier of the American Revolution that she was age 52 years. If this is true, she was b. ca. 1790. Since she had children as early as 1791, this seems unlikely.
Peter Allan received the pension in 1838, 1840, 1841 and (listed as deceased) in 1843. In 1843 it was indicated that he was age 79 years in 1840 (b. ca. 1761.) A deposition dated 5JAN1838 indicates that Peter Allen of Douglas Parish, York Co., NB was a private in the 4th Battalion of the New Jersey Volunteers for 7 years, and was wounded at Burnt Meadows on Staten Island. He was age 76 years (b. ca. 1761), lost his discharge in a house fire and had never received a crown grant. Dorcas receives the pension in 1842 (suggesting Peter died in that year) and 1843 (age 69 years, b. ca. 1774.) So far, I have seen nothing that might suggest she was age 52 in 1842. That she was b. ca. 1774 in 1843 suggests, again, that she was Dorcas Gallop, d/o Nathaniel and Hannah (Parent) Gallop b. 28FEB1774.
Add to this that Peter Allen was petitioning in Sunbury Co. in 1785 (with John, Lawrence and Thomas Allen and others) and again in 1786 with Dolph Brewer. Also in Sunbury Co. in 1788, Queens Co. in 1790 and Sunbury Co. again in Sunbury Co. in 1793. It was not until 1803 that he petitions in York Co. (with the Brewer's and others.) In 1818, he petitions with Solomon Fairley (who, by the above, is the Solomon Farley who m. Mary Gallop, and, by my theory, was his wife's brother-in-law.) Solomon Fairley was petitioning with Dolph Brewer in York Co. as early as 1793; so we know that Solomon was very likely acquainted with Peter Allen. Solomon Farley petitioned for land in Queens Co., NB.
Contrary to his claim, Peter Allen was granted land (with the Brewer's and other Allen's) in Sunbury Co., 21JAN1788.
Daniel "Jouett" m. Lydia Gallop in Sunbury Co., NB 1JUL1802. He was of Queensbury Parish, York Co., but obviously would have connections in Sunbury Co. Lydia was resident in Burton Parish, Sunbury Co. Nathaniel Gallop is in the Sunbury Co. Poll Book of 1795 as being in Burton Parish. Whether this is Nathaniel, Sr. or Jr. is immaterial, as it establishes the family in Burton Parish. There was also an 'Ian/Lan?' (Lawrence?) Allen.
Thomas Burpee m. Sunbury Co., NB 13JAN1789 Esther Gallop; suggesting yet another connection between the two families.
This indicates that Peter Allen was in the right places, connected to the right people and of the right age to marry a Dorcas Gallop b. ca. 1774. thus, Dorcas, rather than being a mother of Robert Haines' wife, would seem to be a contemporary, i.e., a sister.
On 15DEC1788, a number of persons in Sheffield and Maugerville Parishes, and adjoining parishes in both Queens and Sunbury Counties, accepted the Rev. John James as Congregationalist minister and also pledged monies towards his maintenance and support at the meeting house in Sheffield. Amongst these were David Burpee, Daniel Jewett, Thomas Burpee, Edward Burpee, Peter Allan and Nathaniel Gallop. This shows another connection between these persons and their families. It was at about this time, apparently, that Peter Allen sought and found a wife. Being b. ca. 1774, it is unlikely that Dorcas married before 1790; and the dates-of-birth of their children suggest that it was just about then that Peter and Dorcas married. It was just about this time that, "At a meeting of the church and congregation of Protestant dissenters who usually assemble for public worship/in Sheffield held in. Sheffield the 6th Day of May 1790", to offer the Rev. James a call to the ministry of their church. ('Documents of Old Congregational Church at Maugerville', beginning p. 119, "Collections of the New Brunswick Historical Society", Vol. 1, p. , Saint John, NB, pp. 139-142. The citation is a bit tricky as I am looking at a badly scrambled scan of the book.)