The following information about Stephen and Mary Richardson's children is probably more accurate than that given by Vinton:

Stephen, born February 18, 1763 (Methuen VR p109)

Daniel, born about 1765, of Sutton, NH (IGI film 170659, p 1094, ref 23956)

The following is from The History of Sutton, NH by Augusta H. Worthen, Facsimile of the 1890 Edition, published by the Town of Sutton, 1975, pp 926-7:
Daniel Richardson, brother to Edmund (see below), lived near him. His wife was Bathsheba Flint. They had four children. He became blind by consequence of an accident, and afterwards supported himself by basket-making and chair-bottoming. He used to go all over town to people's houses, and do their chair and basket work. He died in this town past 60 years of age, and his family removed to Amherst [NH].

Hannah, born November 8, 1765, Methuen VR, p107)

Nancy, born about 1767 of Sutton, NH (IGI film 170676, p 295, ref 48395)

Solomon Austin came to Sutton from Amherst about the year 1800, and settled in the vicinity of Edmund Richardson (see below), who was a brother to the wife of Mr. Austin.(History of Sutton, p 601)

Methuen VR's show that Solomon Asten and Mrs.Hannah Richardson expressed their intention to marry on June 1, 1784 (p139). It is possible that Hannah (Anna) and Nancy were one and the same person, since Nancy was a common nickname for Ann and similar names.

John Barnard, born January 28, 1768 is registered simply as Barnard in the Methuen Vital Records, (p 107), but his headstone in the Hockanum Cemetery of Hadley, MA is engraved as John B. Richardson.
Mary, born about 1769 of Dracut (IGI film 170676, p 300, ref 48540)
Sarah, born about 1771 of Dracut (IGI film 170676, p 323, ref 49194)

Edmund, born about 1773 of Sutton, NH (IGI film 170659, p 1105, ref 24196)

The History of Sutton, NH pp 926-7, tells of an Edmund Richardson who died there without issue on January 14, 1868, aged 92. He had married Betsy Gile of Haverhill, MA.

Haverhill VRs 2, 266 shows that Edmund Richardson of Methuen married Betsy Gile, December 12, 1796, which agrees with Worthen's account.

Aquila, born about 1775 of Methuen (IGI film 170659, p 1109, ref 24282)

Dracut Town Records, p 384, dated December 31, 1790 list the following children warned out with Stephen Richardson, laborer, and his wife Mary: Mary, Edmund, Elizabeth, Sarah, Anne, Daniel and Aquila.
It is not known whether Elizabeth was an additional child, not listed elsewhere, or an error for Nancy.

Warned out at the same time were:

Stephen Richardson, Jr., Laborer, his wife Susannah, and their children, Stephen and Susannah.
Barnard Richardson, Laborer
Samuel Gardner, Laborer (probably Stephen Jr.'s father-in-law), his wife Anne, and their children, Samuel, Joseph, John, James and Paul
Six pages of other men mostly listed as laborers, miners, or gentlemen, and their families.

Stephen, Stephen Jr., and their families were still in Dracut in 1800, according to the census for Middlesex County. In fact, The Massachusetts and Maine 1798 Direct Tax Assessments show that they both owned land and houses there - nine acres for Stephen and two acres for Stephen, Jr. (See the website of the New England Historic Genealogic Society) The Middlesex county deed indices, however, show nothing in either of their names.