Re; Hearing shots
Shooting indoors is very different than shooting outside. Shooting indoors causes reverberation. It's kind of like filling up an aquarium. You drop a pebble in it and the waves in the water that it makes are contained. You'll see the ripples flow out but they hit the walls of the aquarium and can go no further, so they roll back, unless there is a leak. Sound waves would be contained much the same way when a firearm is shot indoors except where sound could escape (open window). However, it's still not going to sound the same, nor travel far, you've got trees, hillsides, the exterior walls of the other homes blocking the waves, the wind carrying the waves in other directions, etc.. One thing is for sure, it would have been deafening in those trailers since most firearms are in the decibel range of at least 120db and that's just an average of pistols/rifles. Some go up 160+ db. An AR-15 can go to 180db. I'd not be surprised if the killers had some sort of ear protection if in fact this was planned. The ones sleeping were most likely completely stunned if they even had time to get their bearings. The babies and toddler should probably have their hearing checked.