Hello99: Even presuming that someone can have halachic ownership over an idea in any circumstance ie; even for Fair Use, with music anyone can easily get around the supposed gezel of the IP. If I was to change a music file in any way, by manipulating the bits that compose the song, I technically haven’t stolen anything. So simply by converting to MP3 format to store on iTunes I would be complying with copyright laws. In a similar concept, you may see shirts with different skewed versions of the Ralph Lauren logo, which is perfectly legal. As long as the idea is not exactly the same it would be okay.
“Once we accept that the accepted Halacha and vast majority of Poskim accept intellectual property “
You still haven’t proven that this applies in non-commercial cases. I cannot fathom how gezel would apply in a case where there is no possible direct or indirect loss to the victim (hence there is no victim), and no returning of said “idea”. Seems to be a massive chiddush of yours that must be first proven clearly for it to have any value.