uruk-hai sounds from LOTR cannot be copyrighted. It is just noise, just like grunting of pigs. Common people, you copyrighted everything. Soundtrack is another thing, but noises... It is so shame not have it in. But I know no one will convince you. You just dont want to.
btw. some models in your mod is the same from movie (uruk shields and so on) - isnt that copyrighted too? (using your logic) it is not your own design. But you still use it. I'm just thinking.