Umm, sorry to disappoint, but if you are going to Universal Studios Orlando on the 12th, you are not avoiding. They do the same thing on the 11th and 12th, and usually market it a little more toward the rock side on purpose (targeting teenagers more as usual). Their event is called "Rock the Universe," and is marketed as "Florida's biggest Christian music festival." It is advertised as being from 4 p.m. to 1 a.m. with a "Youth Leader Lounge" for youth leaders to get a respite from the groups they are chaperoning.
https://www.universalorlando.com/Events/Rock-The-Universe/Event-Info.aspx
And as
@Nick Wilde has noted for himself, and as I posted above, it seemed nice and manageable from a guest standpoint when I went two years ago. I am sure there were some problems in the background, but overall I found the crowds (yes, even in the Space Mountain and Big Thunder switchbacks) to be fun and positive. They were mostly high-fiving one another and laughing and smiling, but yes mostly youth groups and their leaders.