Sorry.No other documents just circumstantial evidence.
One of the older children of David and Susan referenced born in Russell VA when they married in Johnson KY so assume that their marriage took place there since the Powers had close family ties in Russell VA. Also, no death certificates were issued in Johnson KY during the epidemics or War between the States.
1) David and Susan's 2nd oldest daughter was named "Creatia" (Lucretia) pointing to Lucretia Phelps, wife of David Lilly.
2) After Susan's death, the younger children were "farmed" out to relatives to raise and the youngest daughter Mary Powers was listed with Joel and Elizabeth Nunley Lilly in the 1870 census for Johnson, KY. (Susan's brother)Sorry no relationship was required for the 1870 census.
3) David Lilly did not mention any other siblings or nieces in his will.Only his wife and his children.I considered the $20 the preverbial 2 shilling as recognition so his will would not be contested by Susan's children or husband.
AS to David, son of Henry Powers and Sarah/Sallie Gobble. He remarried in Floyd KY to Eliza Fortune White, widow,in 1878 and his unmarried family was back in Washington VA in the HH of Henry and Sally in 1880 as son, daughter in law, and grandchildren. Joel Lilly and Elizabeth Nunley had also returned to Washington VA with Mary Powers listed as sister in law in the HH of James K Polk Musick and Susan Catherine in Floyd KY.
David's death certificate in 1911 in Boyd KY listed parents as Henry and Sarah Gobble. They evidently returned to Kentucky apx 1892.This would make him oldest brother to Abner Powers.The informant was Eliza Powers, who would be quite knowledgeable considering she had lived with his parents.
Henry Powers and Sarah/Sallie also must have married in Russell VA where his parents lived until 1827.Going thru the process of elimination of the enormous Gobble family of Washington VA we get down to Isaac Gobble( d. 1828) and Elizabeth Musick's (d. 1844)daughters.All family history records have indicated that "Ann married a Powers" and "Sarah died young."No Powers married to "Ann Gobble" can be found and there is no other missing "Sarah".
Will send more privately so this doesn't get too lengthy.