In the 1850 DeSoto Parish census, p.189, Household 407 is Thos. F. Tharp, age 27, Planter, b. MS. Adelade, age 25, b. AL and Walter b. LA. There is some confusion about Walter's age - there is an "m" over a 9 as though the enumerator started to record his age as 9, but realized it was 9 months. Next door is G. A. Tharp, age 58, probably Thomas's father.
1860 Census. DeSoto Parish, Keatchie, Hh 561
1870 Census. Burnham, Ellis Co TX, Hh 112
I did not find them in 1880.
After looking at the above website, it is apparent that Thomas was Thomas George Allen Tharp, a preacher, b. 15 Sep 1825 in Copiah Co MS. He was the son of Anna Spencer and George AllenTharp. The name was originally Allentharp but over the years became shortened to just Tharp. George, the father, was born about 1791 in Bourbon Co KY and died Nov 1851 in DeSoto Co LA. Thomas was their 5th child of seven. Anna Spencer died prior to 29 Nov 1832, when George married Martha Amanda Bullard in Hinds Co MS. He had six more children by Martha, the first, born about 1833 was Elizabeth, or Eliza, Allen Tharp who married Alexander McCorkle Haden, Adelaide's older brother.
Adelaide HADEN and Thomas G. A. THARP were married on 28 February 1849 in Desoto Parish, Louisiana.424 Thomas G. A. THARP was born in 1823 in Mississippi.