I do not believe that this Sarah How is the Sarah How that married John Ballard, son of Sherebiah and Lydia (Osgood) Ballard.
Andover VR does not have a Sarah How (or Howe) born in October 1721. There is a Sarah How born " d. [Dr. CR2] Israel and Marcy, Feb. 7, 1721-2." This Sarah How is Sarah Kingsbury Also, the Abbott genealogies for Howe and Ballard (https://mhl.org/sites/default/files/files/Abbott/Howe%20Family.pdf [page 2] and https://mhl.org/sites/default/files/files/Abbott/Ballard%20FAmily.pdf [page 21]) have Sarah, daughter of Israel and Marcy Howe, marrying John Ballard, son of Sherebiah and Lydia.
Please supply documentation to support that Sarah How who married John Ballard is the daughter of Jonathan Howe.
Marlborough VR (https://ma-vitalrecords.org/MA/Middlesex/Marlborough/aBirthsH.shtml) has a Sarah Howe "d. Jonathan [Jr. CR] and Sarah, Oct. 25, 1721."
Marlborough VR has 3 possible husbands for Sarah - Benjamin Hoar, Mar. 4, 1745-6.; Adonijah Church, Apr. 10, 1747. & Simon Gates, Nov. 30, 1749.
Of these marriages - Benjamin Hoar married Sarah (Hapgood) Howe according to http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=24563992. This Sarah Howe is Sarah Hoar
https://ancestors.familysearch.org/en/998G-VNY/sarah-howe-1721-1758 has Sarah, daughter of Jonathan Howe & Sarah (Hapgood) as the wife of Adonijah Church. He is the son of David Church & Mary Wilder. This David Church is NOT David Church, of Watertown and Killingly See https://www.wikitree.com/wiki/Church-135 for a good description of the problems of the two people named David Church.
Thus, Sarah Howe, daughter of Jonathan and Sarah (Hapgood) Howe, needs to be disconnected from her two husbands and children. The husbands and children belong to Sarah Howe, daughter of Israel & Mercy.