Autosomal DNA: Triangulation. S. Massey (Rebecca great-granddaughter) shares segments with a descendant of Rebecca's brother (James Sanders Alderman) at 23andMe that are also shared with a descendant of Rebecca's paternal aunt (chromosome 3, position 115-179). Also on this segment are two FTDNA matches (one on GEDmatch: M183552) who also have different descents from Rebecca's Alderman (and related) relations. See also chromosome 4 (position 32-63) where S. Massey matches two people at 23andMe who have different descents from Rebecca's relatives on the Alderman line.
It may be possible to confirm family relationships with Rebecca by comparing test results with other carriers of her mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Rebecca: