1850 North of the Yalobusha River, Yalobusha Co., MS
Household #883
Lewis Vanhorn 40 MD (supposedly Charles Dalton Vanhorn)
Jane 32 AL (Jane Kelley Mitchell)
William 7 MS (William Pinkney Vanhorn)
Anna 5 MS
Felix 4 MS (Benjamin Felix Vanhorn)
Mary 3 MS

1860 N E Beat, Yalobusha Co., MS
Household #307
Jane Vanhorn 45 AL
Wm 17 MS
Ann 15 MS
Felix 12 MS
Lucy 10
Henry 8
Andrew J 8
Mary Jane 6

In my opinion, Lucy in Jane's household was actually Rebecca Frances "Fannie" (nee Vanhorn) McAdams, and the two eight-year old children were actually John Randolph Vanhorn and his twin, Cynthia (nee Vanhorn) Easley.

How did they get to be Powell in 1870?

1870 Twp. 12, Range 1West, Calhoun Co, MS
Household #209
Jane Powell 52 AL (Jane (nee Mitchell) Vanhorn
Francis 18 MS
John 16 MS
Cynthia 16 MS

Rebecca Frances "Fannie" (nee Vanhorn) McAdams - FAG #20439190
John Randolph Vanhorn, born 14 Feb 1853 - FAG #85164688
Cynthia (nee Vanhorn) Easley, born 14 Feb 1853 - FAG #23955763

Felix married 1st Dec 1869 the daughter of James D. Hill and Margaret Lewallen, Alice Hill, and they are on the 1870 Calhoun Co., MS census with the date of their marriage on the census image.

1870 Twp. 14, R 1East, Calhoun Co., MS
Household #166
Felix Van Horn 23 MS
Alice 15 MS

Alice passed away before 1879 and Felix married 2nd the daughter of George Washington Sturdivant and his 2nd wife, Frances Zella Y. Nelson, Martha "Mattie" Sturdivant. Martha was also the niece of Andrew J. Nelson and his wife, Emily Broom of Yalobusha Co.

Mississippi, Compiled Marriage Index, 1776-1935
Yalobusha County
8 Jun 1879
Benjamin F Vanhorn
Martha Sturdivant

1880 Yalobusha Co., MS
Household #441
Felix Vanhorn 33 MS PA AL
Martha 22 GA GA GA
Evalena 9 MS MS MS (Alice's daughter)
Elisabeth 5 MS MS MS (Alice's daughter)
Charlie one month MS MS GA

Felix died ca. 1884, and his widow, Martha "Mattie" (nee Sturdivant) Vanhorn married 2nd Abner B. Williams 3 Jan 1885 in Yalobusha Co.