The Andover VRs record the births of two Phebe Lovejoys.
Phebe, daughter of Henry (Jr.) and Phebe b. 20 Sep 1735
Phebe, daughter of Hezekiah & Hannah (Austin) b. 24 Oct 1737
One Phebe married Davis Walton abt 1753 in or near Amherst, NH
One Phebe married Daniel Austin 9 Oct 1756 in Andover, Mass. This Phebe (Lovejoy) Austin died 29 Sep 1802 "in the 67th year of her age" and was buried at the South Cemetery, Lunenburg, Mass. (see: http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=AU&GS...;)
mtDNA testing of a direct "umbilical" (all female line) descendant of Phebe (Lovejoy) Walton proved she was the daughter of Hezekiah & Hannah, as she was a full match to a direct umbilical descendant of Phebe's sister, Hannah (Lovejoy), wife of Jacob Stanley.
Thus, the wife of Daniel Austin would have been the daughter of Henry (Jr.) and Phebe.