It appears the Brewers and the Blackburns were from Hickman Co., TN.See below from Rootsweb's WorldConnect site.Lucinda Blackburn was apparently married 4 times, according to this entry.Maybe you can contact the person who entered this info for more sources.
The first settlement on War Eagle Creek, in Benton County, was made by two brothers known as bear hunters, their names being Isaac and Levi Borne. They came from Illinois early in the spring of 1832, and settled above the present War Eagle Mills, and each one raised three acres of corn that year. The following fall Absalom Thomas, Henry Taber, Lewis Russell, Robert Taber, William Brazeel and a Mr. Nelson all settled with their families in that neighborhood, and in December of that year Sylvanus Blackburn, Josiah Blackburn, Julius Kirk and Matthew Brewer with their families, all from Hickman County, Tenn.,settled in the same neighborhood. The latter party came by way of Springfield, Mo., and, crossing what is now the line between Missouri and Arkansas, on the old State road passing north and south, they reached the cabin of John Fitzgerald, then living near the present village of Lowell, and stayed there over night. The next day, leaving their families at Fitzgerald's, they prospected for and selected their respective locations, and then moved thereon. Sylvanus Blackburn located on the place, at the present War Eagle Mills, where he and his estimable wife, who then accompanied him, are still residing, he being in his eightieth year at this time,and she being about the same age. Julius Kirk settled on the creek about half a mile below the mill site and Matthew Brewer about three-fourths of a mile above it. Mr Blackburn and his wife are the only survivors of these settlers. Reference: Goodspeed History of Northwest AR, Benton Co, pp.24-25 pub. 1889