So, someone should make a mod where playing music can give buffs to surrounding party members, or maybe even giving debuffs to monsters/non-party members. If you really want to get fancy, maybe you could give different instruments different effects. So like, for example, you could play a song with your Electric Guitar and get your friends fired up in battle, giving them a small attack boost. This could even be used with the one-handed instruments mod so that you aren't totally defenseless while playing. (I don't know, this is just an interesting concept I had, and I would love to be able to have a better reason for randomly playing music while other people are doing all the work. )
Seems like a great Idea basically adding a "pacifist" way of fighting and would be great even for a general playthrough if you would get those buffs yourself and if they would last from 1 minute to-10 minutes depending on how strong the buff is(I mean like you play an intrument and the stronger the buff the less time the weaker the buff the more time) and I think there should be 1 handed and 2 handed instruments to be able for this thing I'm saying to make actual sense and be usefull