I think that 3000 slaves is a wee bit of an exaggeration. By 1860 the two brothers had 29 slaves between them, at least recorded in the 1860 census. After the emancipation in 1865 it is doubtful that they had more, in fact, fewer because they probably gave them their freedom.
If you look carefully at the census information I sent you in my last post you will see that Melinda (Malinda) is the wife of Luke Peak and that Kessiah is the wife of Jacob.
I'm sure you are aware of the Peak-Hornsby Cemetery on the pennisula connected to the Meigs County Park? If not, you may find additional information by searching there.
That's about all I have time for. Good luck in your search.