The Lomax recording (mp3 of II above) is HERE. Alternate version (titled "My Time Ain't Long") is HERE.

The Burleigh version (words) posted by Pene Azul is HERE in the forum. We can see the 1918 sheet music HERE.

Though Jame J. Fuld says, "The first known appearance in print ... is in William E. Barton, Old Plantation Hymns, copyrighted Feb. 6, 1899, ..., under the title Motherless Child" (The Book of World-Famous Music, 4th ed., p. 514), it was preempted by the same version, also titled "Motherless Child," in the Barton article "Hymns of the Slave and the Freedman" (in New England Magazine, Jan. 1899; with music), which is reprinted in Bernard Katz, ed., The Social Implications of Early Negro Music in The United States (Arno/The New York Times, 1969, p. 91):

MOTHERLESS CHILD

1--
O, sometimes I feel like a motherless child!
Sometimes I feel like a motherless child!
 O my Lord!
Sometimes I feel like a motherless child!
Den I git down on my knees and pray, pray!
 Git down on my knees and pray!
O, I wonder where my mother's done gone,
Wonder where my mother's done gone,
I wonder where my mother's done gone.
Den I git down on my knees and pray, pray!
 Git down on my knees and pray!

2--
O, sometimes I feel like I'd never been borned,
Sometimes I feel like I'd never been borned,
 O my Lord!
Sometimes I feel like I'd never been borned.
Den I git down on my knees and pray, pray!
 Git down on my knees and pray!
O, I wonder where my baby's done gone,
Wonder where my baby's done gone,
Wonder where my baby's done gone.
Den I git down on my knees and pray, pray!
 Git down on my knees and pray!

3--
O, sometimes I feel like I'm a long ways from home, etc.
I wonder where my sister's done gone, etc.

4--
Sometimes I feel like a home-e-less child, etc.
I wonder where de preacher's done gone, etc.

~Masato