Before our team works any further on chairman’s, we were wondering if changing the lyrics to a song and performing it was allowed. We would play the music live, but the sheet music comes from an existing band. Is this allowed or would we have to write our own song? Thanks so much in advance!
I’m pretty sure it was allowed last year and I haven’t seen any changes, so I’d say yes, it is allowed.
Based on FIRST’s love of parodies I doubt you would have an issue with them, the artist may be another matter, unlikely, but still a possibility. But rules are rules, in part it’s up to you how they are interpreted.
If you change enough of the song that it could count as a parody, then you may be OK but in general if you want to use any materials with a copyright, you need permission from whomever holds the copyright to be able to use it.
With some googling, you can generally find who you need and after a few phone calls you can get the permission you need provided the artist isn’t too big.
As for the FIRST side of things, I don’t know of anything that disallows it. But copyrights are copyrights are copyrights, regardless of in what medium you’re using the copyrighted material. This thread has lots of information about using music in reveal videos, and the concept is the same.
Wait a second.
You would perform the music live??? You mean, bring instruments and gear and play the song for the judges during your presentation?
There’s a few potential problems. You might be able to skate on E11 and/or E12 (no live bands/loud music in the audience/pits respectively), but that should be something to think about. And, if you look at http://www.firstinspires.org/resource-library/frc/submitted-awards, you only have 7 minutes to present, including setup. And setting up in <7 minutes isn’t exactly easy, even for pros who are planned for with all the equipment drops in place.
If you’re talking about putting that in your Chairman’s video, remember that that’s only 3 minutes long.
If there’s instruments involved, I’d say keep them small. Your seven minutes of presentation time generally starts when you walk in the door (although it can vary from event to event). If it’s just woodwind/brass or small percussion instruments assisting vocals, that could work nicely.
Just as a side note, parodies of existing songs fall under Fair Use in copyright law, so you should be fine in that department! 
Our team did not perform live, however we used this song for our chairman’s video: https://www.youtube.com/watch?v=DFBkttmtMLw
It is definitely allowed and the judges were thoroughly entertained.
I highly suggest that if you are to perform a song live for your presentation you have everything extremely organized. As for the music, I always lean on the side of royalty free / written yourself music.
I answered some more chairman’s questions, including this one, in the team’s vlog this week. You can see more of my thoughts here https://www.youtube.com/watch?v=rRkWN6U_Vxc