For what it's worth, here is my current theory.....I think 1 person murdered Kenneth as a crime of opportunity - this person had nothing to lose and/or something to gain (in their own sick twisted mind) after this person had heard the knews - maybe it was money this person was after, maybe it was drugs, maybe it was both, who knows? Several things make me think this way but only one I can discuss here is that Kenneth was not found until hours later. I don't think (as of now anyway) that Kenneth was involved in as many things and/or as close to the family as the others were with each other. I have nothing to back it up, this is all JMO from reading and observing here and there.
I think it's highly possible also that 1 person murdered the other 7 and I don't think this person had any family ties but rather was someone who had at one time voiced threat (s) against the family. This person is male and has been questioned (in the early stages). I think it was out of anger/revenge and the reason I think it was carried out by one person was because you can't tell on yourself (versus having others involved who can or may talk). The question I ask myself is could somebody actually be so upset with 1 or more members of a family over some threats or name calling etc that they would actually go murder their entire family? Yes, that is hard to grasp, but then again, maybe there were involvements amongst them regarding other things? Also, IMO a person who could shoot this many people, most of them while they were sleeping, obviously has issues so that's why I then tell myself that people have killed for lots less reasons because they obviously are mentally disturbed!!! And this person may have even went to one of the houses or all of the houses for that matter to fake an apology or to try and make amends so therefore was willingly let in and then it all happened from there. These 7 family members were all in close proximity of one other, I don't think it would've taken long to complete the mission he was on. Possibly this person was let in, shoots the first person and heads directly to the next 1 or 2. Even if the shot wasn't silenced in some way and you were in a deep sleep and heard a gun shot, you would almost have to have a weapon under your pillow to be able to wake up, grab it and try to protect yourself before someone runs down the hall to shoot you next (especially in a trailer where there aren't that many rooms to wonder which ones are bedrooms etc).
I also think the person who murdered the 7 family members was young, inexperienced, more than likely not much experience with shooting as in even target practice etc and that's why it took the number of bullets it did. Again, JMO.
This is all JMO and it is my theory for right now but is subject to change as it has changed numerous times already since I started following this case from the beginning.
