If someone wants their submission to have any audio, does said audio have to be made by someone on their team? The phrasing of the rule about original material makes it sound like it does, but I just want to make sure.

You can use any graphics or audio from online or other sources as long as it is Copyright Free, such as but not limited to (Copyrighted Music), because the games will be broadcasted on livestream, and if there is a song that is copyrighted the channel could face a copyright strike depending on how the artist reacts. Sorry for the confusion, I will be updating the description to prevent further confusion.