I am not certain of what Wolfe meant by Talley sending Florence Botsford "an original composition called "Behold That Star."" She was requesting songs for her collection, "Folk Songs of Many Peoples," not original compositions.
I have Botsford's book with the song. "Behold That Star" was published as "U. S. A. (Negro), Melody by Thomas W. Talley, Words by Thomas W. Talley," p. 47, with music, 1922, in "Botsford Collection of Folk-Songs, Vol. 1, Songs from the Americas, Asia and Africa," G. Schirmer Inc. New York. Did Talley say that the song was original with him? I would guess that his papers would indicate that he had the rudiments in his collection and fleshed it out for Botsford.
(Seeger's comment is one of those 'off the top of the head' remarks he was prone to make and should be given no credence. )

The refrain of "Behold That Star!" is similar to the refrain of "Hail dat beautiful star" of the Nashville Students, 1884. The verses are entirely different. The relationship is conjectural, but possible, as you suggest. The melodies are not the same. I would not doubt that other versions exist about the 'star.'

There are many old unremembered or poorly remembered African-American religious songs that are not readily available; the little pamphlet I found is just one of many that were produced in the 19th c. and seldom found.

"Rise Up, Shepherd, an' Foller," a song about the 'star' from the Hampton Institute (see Dett), is another that Botsford included in the book I cite above. I keep looking for 'star' songs, because I think that one of them is the basis for the little verses on which rest the "Drinking Gourd" nonsense. It takes money that I don't have to get the old camp meeting books.