I'm not going to make money off of it, I'm just doing it for fun. Plus, people use windows error sound effects in a lot of remixes and Microsoft doesn't sue anyone. Plus, I would be making it transformative by using it in a remix. Oh, and lots of other people have used Kingdom Hearts voice clips in remixes and it's ok. Square Enix is ok with letting people use their sound effects, unlike some other game companies. When it comes to music, Square seems a little bit protective with that (which is totally understandable), like if you wanted to do a let's play of Kingdom Hearts, you would have to mute the opening theme to avoid getting a copyright claim on the video.
Quote from VinceOnAPlane(Reddit User):
"I primarily do video game covers (won't post a link in here, but feel free to check my post history for stuff I've shared). There's nothing illegal about doing it at all! Infact, you can get most video game music monetized through an intermediary like Loudr.fm which will pay royalties to the original game developer/composer.
Disclaimer: Nintendo is the only major game developer that's against this, which means their first-party franchises such as Mario, Zelda, Pokemon and Metroid can't be licensed in this way (however you could do for example, Mega Man, Street Fighter or Final Fantasy games that were on Nintendo systems). There's nothing stopping you from covering their music, but monetizing it for direct sale isn't an option."
