BBM
Gotcha. The overkill alone, speaks to unleashed anger, to me.
Maybe. It could also just be insurance to make sure no one survives long enough to call 911 or grab a weapon and return fire. JMO, these killings happened pretty fast. Killers were probably very twitchy and kept shooting anyone who was still moving. With the exception of CR1's wounds, I've never thought the number of wounds, 2 or 3 or 5, was significant considering they may have been semi-automatic weapons. It probably took just as much time to fire 5 shots as it did 1.
Also important was the ability to get into these homes in total darkness and ambush the victims in their sleep, shooting them with deadly accuracy, without giving them much time to react and without hitting the babies.