I think you definately did the right thing again. I also think you shouldn't give up on talking to them just b/c one is being nasty. If he is a known trouble maker and continues to be nasty like he is, then maybe the band will boot him.
I wonder if you could get the Humane Soc involved b/c they are terrorizing your cats. Would that count as animal cruelty? Would be an interesting approach.
And if the band/family/kids find out that other neighbors are bothered by it too, they might find somewhere else to pollute with their noise!