OK, I get it about the loud music (nothing new, remember boom-boxes in the 80s?) and rowdiness. But nothing wrong with drinking or smoking a joint outside.
As far as kids, they should be in bed by 10-11, but the assertion that they should live on the bottom floor is frankly retarded. That would mean that in a ten-story building, only 10% of the apartments would be available to families.
Parents should be considerate and control their kids. I live below a couple with two kids and don’t have the same issues. The operative word is “lowlifes” not “kids.”
Lastly, you could always fight fire with fire. Get a giant woofer, attach it to the ceiling, play a particularly violent action movie through a 500W amplifier. Go for a walk at 6 am.