Research of this kind is difficult. Not easy to get material from many institutional archival collections. To check microfilm or boxed archival material you must present yourself. No librarian can spare the time to go through newspaper films or boxes of archived material unless you can specify the exact item wanted. Many turn down email requests and internet search of their catalogues (only the well-funded ones will have this) is limited to those within the system.
In researching topics concerned with the West, on occasion I have gone outside of the local university and local archives. A charge, or donation, was asked for after I received an introduction. In addition, I knew the periodical and the article or news item I wanted. Even locally at a museum archive I was not allowed to copy an image, but had to go through the curator, schedule an appointment with the staff photographer, and pay for his work. In addition, I agreed not to publish on the item without their approval. This is not unusual.
I posted the original version of a song here about a year ago on which I knew the exact issue of the mining town newspaper in which it appeared and it cost me a $20 "donation." The archive lacked a good scanner and it took them several tries to send me a legible copy by email. They also don't have the money to digitize or microfilm that old newspaper, important to local historians, of which they have the only copies.
If I were a member of a university staff or an enrolled graduate student, I would be able to do much more. At a couple of schools, I have a friend who will check institutions in his state system. I have no such contacts at the likely sites for the information wanted here. Newspapers in the towns where the minstrel troupes appeared would need to be checked (routines varied from town to town and the better troupes revised material for each major stop).

It might be easier to find out if there is a Hays archive or a thesis on W. S. Hays. Most large universities have lists, or can get them, of theses done at American and Canadian institutions. If an archive of Hays' papers can be found, however, then arrangements may be made for someone to go through them, searching for pertinent material. Do not expect the archivists to do it for you. Present yourself (or proxy), don the little white gloves, and have at it (after, of course, you have ben vetted).

Changing the subject back to Dixie, why did Emmett call his minstrel piece "Dixie's Land"? (original title) and not simply Dixie, as it later became? Another unanswered question.

Was there an authorship dispute in reality? Was it between the two authors or between two minstrel troupes? The two books Masato and I have mentioned may have something on this, and would be the first place to look.