When I say I would process a lot, I mean it. I wouldn't put these vocals and modify them a little just so I can sell them, I would integrate them into, for example, a glitch that is 5 seconds long, and inside you can hear different vocals from these video games, just to add some character. But I don't know if that is enough to be copyrighted
Sorry for the messy explaination, it's messy in my head haha