- 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, then you infringed its copyright, regardless of if there is an licensable version of that melody that you could have copied. What matters is which one you copied, not the existence of alternate copies.