The Joshua Arnold/Arnall who died in Wilkes Co., GA in 1807 would probably be the son to the Laurens Co., SC Joshua Arnold/Arnall. I find a Laurens Co., SC Joshua Arnall who left his will in Laurens Co., SC in 1791 naming his wife, Leanna Franks Arnall, his daughter Martha Arnall (who married Robert Bumpass), and giving property that he owned in Abbeville Co. to Joshua Arnall Jr. and Joshua Franks. I have not been able to find this property yet but I have always believed that the Joshua Arnall Jr. moved on to Georgia after his father's death.
I would be very interested in knowing what data you have on your Joshua Arnall as I also believe that he has something to do with my own Zachariah Arnold of Abbeville Co., SC.
SCMAR, Vol. VI, Fall 1978, No. 4, p.225 Pp. 34-36: Will of Joshua Arnold of Laurens County…to wife Leanna Arnall, all reall and personal estate, and at her death to my only daughter Martha Arnall; should she die before her mother and without issue, 100 acres whereon I now live to Joshua Millener, with all my personal estate, and 200 acres lying in Abervel [Abbeville] County to be equally divided between Joshua Arnell and Joshua Franks…Charles Smith and Samuel Franks, Exrs… 5 March 1791. Joshua Arnall (Seal), Wit: N. Franks, Robert Franks, Poley Franks (X).
SCMAR, Vol. VI, Fall 1978, No. 4, p.225 Inventory of the Estate of Joshua Arnall, 14 July 1791, by Nathan Barksdale, Charles Allen, Charles Smith, before Joshua Saxon, J. P.