Joe, I think I found the source of the Roud- and Trad. Ballad Index reference to "1907" repertoire of the Fisk Jubilee singers-

John W. Work II and Frederick J. Work, "New Jubilee Songs as Sung by the Fisk Jubilee Singers," 1901. Wade in the Water was first published in that book, which is rare.
"Go Tell It on the Mountain" may also be in that volume. 1907 may be an error for 1901; I doubt that there was another edition in 1907.