There were several McKinney families. This is my feeble attempt to sort them out...

Family Group Sheets with notes and sources

1) John (bef 1755-1804) & Jean McKinney of Rutherford Co., NC

          Their children:
          John McKinney, Jr. (2 Sep 1760-?)
          Henry McKinney (1761-abt 1837)
          James McKinney (between 1760-1770 -1841)
          William McKinney (abt 1772-17 Dec 1857)
          George McKinney (27 Nov 1774-1853)
          Jane 'Jennie' McKinney   
          Mary Ann McKinney
          possibly Margaret McKinney
          Sarah Ludia 'Sally' McKinney
          Dedami McKinney

Documents for the family listed above (courtesy of Bill McKinney of Spartanburg -- Thanks, Bill!)
          Heirs of William McKinney (probate document)
          Heirs of Henry McKinney, Jr. (probate documents pages 1, 2, 3, 4)

2) William McKINNEY (1766 - 1857) born VA, died Cleveland Co., NC  Wife unknown

    Children:
        Susannah McKINNEY (1 Mar 1785 - 13 Feb 1866)
        Burnis McKINNEY (1780/1790 - After 1857)
        Polly McKINNEY
        Sally McKINNEY (About 1800 - After 1850)
        Bedy McKINNEY (About 1792 - 23 Sep 1848)
        Willis McKINNEY (About 1796 - )
        William H. McKINNEY (About 1801 - )
        Aletha McKINNEY (4 Mar 1801 - 28 Jun 1890)