Small correction regarding Jowell. Chrystie Abercrombie b.1746 is said to have been married to Ratcliff Jowell b.1737. Ratcliff Jowell had a son Richard b.abt.1764 (with no known children) and a son Gabriel b.abt.1773 who married Rebecca Abercrombie, dau of James (& the one who left the 1820 will in Laurens SC). Gabriel did contest his father-in-law's will.
Martin Dial was married to another Chrystie Abercrombie, one born later than 1746.
Before coming to SC, Ratcliff Jowell was in Lunenburg Co VA and appears on that county's 1764 tax list. I would think that son Richard was probably born there. Are there any indications of Abercrombie's in that area? Some other names on the 1764 list that also occur later in Laurens: Ragsdale, Rhodes, Matthews, Moore, Mason, Hill, Samuel Cochran, McNees, Mastin (I'm sure there are others, too).