whoever did do this had a huge amount of rage against one or more members of the family and that spread to taking that rage out on all the family members who were present, I don't see this as being about drugs, cars or money per se,
to me this is a personal crime, as not all family would have been involved in the pot/drug business, and not all of them involved in the car business, but all were family,
and it was somebody very familiar with the family and the homes and who lived and slept where they did, whether it was one or more people the crime was carried out in a manner that meant the killer/s got into 4 homes, homes where the owners had and used guns for hunting, then were able to kill all the adults without harming babies or children who were in very close proximity to the adults they intended to kill,
all this in the dark and on land that had lots of cars laying around, dogs all over the place, chickens/roosters and outbuildings plus whatever else was laying around,
I also think LE have no idea what the motive is, and whoever the suspect/s are the motive will be something that was a very close family secret that not many outside the people killed know about, and if the killer/s keep their mouths shut and carry on behave as they usually do then LE will struggle to catch them,