What are the rules on outside help? Say, we had a couple people we knew who played different instruments, and gave them credit for the music, could we use them?
Music and sound is acceptable to source (must cite, but otherwise OK). Anything else should be done by team members OR be preapproved. I'll try to publish the list of already approved stuff ASAP.
IN GENERAL: If it's part of "stock" unity or unreal (no "asset store") you're good to go, anything in Unity Package Manager is fine, other than that you need to check in. Generally the bars we look at when determining approval are:
"Should a student in one of our programs have reasonably been expected to create this themself?"
"Is this trivializing the need to actually USE the skills the students SHOULD be doing themselves?"
For example, a shader for water effects is probably going to be approved since it's both out of scope for teaching at high school level *AND* it's probably not having much of an effect on the overall gameplay or circumventing student need to use their skills.
No Game Dev program I'm aware of in the state has a sound engineering component or is paired with a program that does) so we're pretty permissive on audio.
Oh, and since the games are being published online (via this itch.io site), anything used must be with appropriate licensing permissions - so copyrighted audio (such as pulling a song off a CD) wouldn't be acceptable. That's not applicable with your specific request but I don't want other people reading this answer to get confused :)