Did the M.E.Church South, keep records of marriages? Have you been able to find any records about W C James, the minister?
Would this record be for your g-grandmother in 1910:
"United States Census, 1910," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:ML3M-2H6 : 29 October 2015), Mallie A Jefferson in household of Sarrah Surratt, Concord Ward 4, Cabarrus, North Carolina, United States; citing enumeration district (ED) ED 52, sheet 5B, NARA microfilm publication T624 (Washington, D.C.: National Archives and Records Administration, n.d.); FHL microfilm 1,375,113.
If it is, I noticed that her child's father was born in Georgia and that the boarder in the household was also born in George of Georgia parents. If you haven't already, you might look for connections between the Brown and Jeffries families in Georgia. It's a long shot but at this point, with 20 years in to it, you're kind of down to long shots.