It appears that Joshua and Samuel Ewing were both sons of Patrick Ewing and Jane Porter and were distant cousins of Ellender Ewing (possibly through both the Ewing and the Porter side). However, this has not been sorted out yet.

Joshua Ewing first appears in the 1787 Personal Property Tax List for the Upper District of Russell County, Virginia. In 1790, he is listed in the 1790 Personal Property Tax List for the Lower District of Russell County, Virginia.

Samuel Ewing first appears in the 1790 Personal Property List for the Upper District of Russell County, Virginia.

A second William Ewing appears in the 1790 Personal Property Tax List for the Lower District of Russell County, Virginia. However, he does not appear again.

According to E.W.R. Ewing, Joshua and Samuel were brothers:

Joshua [Ewing], appointed as grandfather's [William Ewing's] associate, was the brother of Samuel, the county's first sheriff.
[E.W.R. Ewing, Clan Ewing of Scotland, Chapter XXVII (1922)]

E.W.R. Ewing is a descendant of William Ewing, brother of Ellender.

Patrick Ewing
Parents: Joshua Ewing
b. 01 Feb 1736/37
d. 11 Apr 1819
m1 Jane Porter, Bef. 1765
   Parents: James Porter and Eleanor Gillespie
   b. cir 1740
   d. bef 1784
Children:
   i. Joshua (II) Ewing
      [named after his grandfather, Joshua]
      b. cir 1765
      m. Rachel Craig, 02 Oct 1788
         Parents: Robert Craig and Margaret Whitehill
         b. 26 Nov 1765 Donegal Twp, Lancaster County, PA
         d. 22 Sep 1820 Lee County, VA
  ii. Samuel Ewing
      b. 1772
      d. 1851
      m. Mary Houston
m2 Elizabeth Porter
   Parents: James Porter and Eleanor Gillespie
   b. 20 Jan 1749/50
   d. 11 Mar 1819 m: aft 1784