I am not a lawyer, but as I understand copyright law there seem to be to be two problems with this: - a copyrightable work must include some human creativity. It seems to me that an enumeration of possibilities might be creative, but there is no way an individual element of that enumeration can be considered creative. - Copyright depends on copying . If you release a song with a catchy melody stolen from another song…
Those are precisely the objections I'd raised with the Damien Rhiel (submitted via email, no response). Additionally there's the problem of releasing the works to the public domain. As discussed a couple of weeks ago when the 2016 billion-dollar infringement lawsuit against Getty Images was attempted ... and thrown out of court ... the act of putting works in the public domain also extinguishes, in the court's eyes,…
Either the courts decide they are not, in which case the creators will be happy.
Or they are copyrightable and therefore this collection, even if it is in the public domain, is a prior art that invalidates any claim that a newly used melody is really new/copyrightable.