You mentioned that you lost track of Susan after the 1860 census.Here is some information I have found on Susan and her family.
Here is information I have for Thomas Sessions and Susan McLemore:
IGI Individual Record - FamilySearch - THOMAS G. SESSIONS - Male - Marriage: Spouse: SUSAN H. M. MCLEMORE - 06 JUN 1850, Chambers, Alabama
Alabama Marriage Collection, 1800-1969 [from Ancestry.com] Name: Thomas G Sessions - Spouse: Susan McLennone Marriage Date: 6 Jun 1850 - County: Chambers- State: Alabama Performed By Title: Justice of the Peace- Performed by Name: John McKnight Source information: Jordan Dodd, Liahona Research
1850 AL Chambers Co pg 304B Line 24 H557/F557 Thomas Sessions 23 wagon maker b GA Susan H 19 b GA [They were the only Sessions list in the online index for 1850 Chambers Co., AL]
Census:1860 AL Chambers Co pg 988 Southern Division PO Lafayette22 Aug Line 16 H709/F709 Thomas G Sessions 32 overseer $600/400 b GA Susan H 27 b GA Mary R 10 b AL Martha J 8 b AL William W 5 b AL Julia A 4 b AL Elizabeth 2 b AL
Census:1870 AL Elmore Co pg 35BTownship 18, Beat No 3PO Tallassee5th Aug Line 7 H1075/F1108 Sissions, Thomas 32rock mason $--/200 b GA Susan 32 keeping house b GA cannot read/write May 18 work in cotton mill b AL Martha 17 work in cotton mill b AL cannot read/write William 15 b AL cannot write Elizabeth 13 b AL cannot write Sarah 9 b AL Mardorah 9 b AL Amanda 7 b AL Emma 5 b AL Ella 2 b AL
Census: 1880 LDS indexBrownville, Lee, Alabama# 218C1st June Thomas G. SESSIONSSelfMMaleW53GACarpenterSCNC Susan H. SESSIONSWifeMFemaleW48GAKeeping HouseSCSC Martha SESSIONSDauSFemaleW27ALWorks In Cotton MillGAGA William W. SESSIONSSonSMaleW25ALWorks In Cotton MillGAGA Nancy C. SESSIONSDauSFemaleW22ALWorks In Cotton MillGAGA Madora J. SESSIONSDauSFemaleW19ALWorks In Cotton MillGAGA Sarah L. SESSIONSDauSFemaleW19ALWorks In Cotton MillGAGA Amanda T. SESSIONSDauSFemaleW16ALWorks In Cotton MillGAGA Susan E. SESSIONSDauSFemaleW14ALWorks In Cotton MillGAGA Ellen J. SESSIONSDauSFemaleW11ALGAGAat home, attended school, cannot write John E. SESSIONSSonSMaleW8ALGAGAattended school [Note: his middle name was Early]
1900 AL Chambers Co pg 58A [ED04-16A], he is listed "Sessions, Thomas G 74 wd b Dec 1825 GA/SC/SC farmer, rents farm # 285" as father of M Richards 47 wd.
Here is another listing which appears to be Thomas' wife Susan: 1900 AL Lee Co pg 266 [ED45-05B] Beat 10, Phenix City [South W RR] [ED 45-5B]2nd June Line 63 152 Third Avenue H91/F97 Sessions, Sarah 69 wd 10ch/3liv b Nov 1830 AL/AL/AL rents house dau Sarah 37 single b Dec 1862 AL/AL/AL weaver, cotton mill dau Ella 30 b Dec 1870 AL/AL/AL weaver, cotton mill son Early 28 single b May 1872 AL/AL/AL slationary[sp?] engineer servant Washington, Mary [black] 45 b Apr 1855 AL/GA/GA [NOTE: Could this Sarah 69 be Susan?The three children match the children of Susan and Thomas G Sessions.Thomas G is listed with a daughter, Martha.Could Thomas G and Susan have been separated or divorced and somehow were listed as widow and widower?They had been listed in Lee Co., AL in 1880.]
Susan's name on her daughter, Ella's death certificate  is given as "Susie McLemore".
1910 AL Chambers Co pg 024B[ED17-2B], he is listed "Sessions, Thomas G 83 wd b GA/SC/SC" as father of Martha Richards 57 wd.