Rolling of the Stones  is already in the DT.  The set at Lesley's site was noted by Eloise Hubbard Liscott from Mrs. Mary E. Harmon of Cambridge, Massachussetts, and was first published in Linscott's Folk Songs of Old New England (1932?). The tune is the right one, but the arrangements on that site can sometimes swamp the melody and lead to confusion. Lesley names the book but not the source singer. Two lines were missing from Mrs. Harmon's version (as quoted by Bronson; I haven't seen the Linscott book); I don't know who has "restored" them, but a few other details have also been altered from the original, including the substitution of at her true love's side for by Bell's side.

The DT set is described as "sung by Joe Hickerson"; I presume that it derives from the Harmon set; the tune is the same. An additional tune is given from The Young Tradition, which appears to be a simplified form of Mrs. Harmon's. Until you find the sleevenotes, I'm assuming that the Bok recording is a collated text made from part of the Harmon set and part of the fragment recorded by The Young Tradition, set probably to the tune they used. They got both tune and text from Oscar Brand. Heaven knows where Brand got it.

Her brother's side seems likely in the circumstances to be a memory lapse on the part of Bok/Muir/Tricket, so I don't think you need to be looking at dark incestuous sub-texts in this particular case.

None of this, of course, brings us any nearer to an answer to Robinia's question. It seems not unlikely that Rosalie Sorrel recorded a text collated from several different versions (common practice at the time), so we really need somebody who possesses the record...