Nathan Harris's surname before he immigrated to Mississippi ca 1875 was Sachar/Shachor, and Hirsh translates as Harris. I'm fairly certain Mera is the Mary )a/k/a Mary Rose / Rose Mary who married Hirsh Sachar/Nathan Harris in 1873, and had seven children who spread throughout the American South. In other words I think you've separated one sons in law of Pesach into two separate men, while there was only one and he married Mera/Mary.