Those white buckets are also everywhere.
I don't have a valid reason, but I still think the initial plan was one thing (burglary OR torture murder) which turned into something else (overnight hostage situation including robbery, etc.) I keep thinking cars were the draw, but then why weren't any of them taken, except the Porsche? I doubt all the others, including Rovers, were manual transmission, if DW couldn't drive stick...
I don't think DW (et al?) arrived at the S house prepared to do much of anything. I think he found the duct tape, the sword, the baseball bat, the white bucket, etc., etc., at the house - although of all the things mentioned, the duct tape is the least likely IMO. I'm sure the S family was more organized than me, but unless it happened to be lying on the counter when he arrived, he'd have to dig through a closet or tool box to find a roll of duct tape, which would be hard to do if you're alone and trying to hold three people hostage until you can tie them up.
Maybe he brought the green vest, but if that was used to reduce suspicion, so someone would open the front door, the person wearing it could not also be wearing a mask. (I think the boot print on the door was not from entry. Again, no valid reason to think that, except LE completely missed the broken glass and possibly broken lock when they initially canvassed the house. If DW came in through the broken door, wouldn't that have been obvious? The boot print may not have shown up until they dusted for prints. No way to know when it was left.) Maybe someone else brought the vest later, or maybe it was in the garage - there seem to be differing opinions on whether green vests were found in the garage and if they had been there before the crime.
Back to knocking on the front door, dressed as a road worker/meter reader/whatever... If DW expected the house to be empty, when VF (AS or PS) opened the door, why didn't he make an excuse and take off? At that point he knows there's at least one person there. Did he think a house keeper was easy to control and wouldn't disrupt his original plan? Was it finding a child and then his mother that upped the ante?
There's one thing, mentioned by others, that makes me think maybe this was more than just a botched burglary/car theft. How did DW know how to avoid the security cameras and how did he know where to find the DVR and disable it? Could he have asked VF/AS about it first thing? Would it take an insider to tell him how to avoid being picked up on the cameras until he could take the security system out? Was it turned off before he arrived by an insider or because it was usually not on during the day?
If LE found a green vest in the burning Porsche, (I saw LE showing it to workers on a news video), if it was in the car, wouldn't the DVR be recoverable also - at least enough to know it was there, even if they couldn't read the data? (Am I assuming the green vest in LE's photo was found in the burning Porsche?) Perhaps the green vest in the photo was only similar to the one seen by W3 or it was found in the garage. IDK
Just want to take a second to share how much I appreciate comparing theories, "facts" and possibilities with all of you. I try to put aside the horror of the crime and "work" it as a giant puzzle. You guys come up with ideas I would never think of, and help me see angles I missed on my own.