If Bronson ( I know nothing of him/her) is publishing public domain materiel they have no copyright unless they have made fundamental changes. Even then it only applies to the changes and if it is not public domain they must identify the source. Is a copyright mark attached to each piece or the publication as a whole? Who is the authour and when did they pass from this world? Did they convey unto Bronson their copyright? Under what country's laws are you asking? The USA is different from much of the world. What do you intend to do with it?
If you believe it to be public domain and you wish to use it for public performance then do so. If you are recording or publishing it list it as public domain and attach no copyright. If the copyright owners object you can always refrain and at least you will know who they are. If it is public domain or based on public domain the burden of proof falls on the claimant. Unless it is a gold record it probably won't be worth their while.
Many people claim copyright to materiel that they did not compose. Don't worry about the "arrangement" crap until the money flows in. Then your lawyer can arrange a settlement, at least partly, on your terms.