The thing that really gets me about this one is how hard it is to apply Occam's Razor. You can get wild with any theories on any case, but usually, the simplest explanation contains the truth. Here? Something wild had to have happened. I don't believe it was SA because I don't think he could have taken her off-site, happened to be in the trailer for a phone call with Jodi at exactly 5:30, gone back off-site and happened to have been back in time to take another phone call from Jodi and have a bonfire with Brendan later. There's just not enough time for all that moving around and it's quite complicated. In order for him to have done that, he would have had to held her somewhere and killed her later. Possible. Unlikely and unsubstantiated by any evidence, but there is an entire 4 days worth of evidence missing, so this is why I would say I'm at #3 on the poll.
For someone else on the compound to have done it, they would have had to have seen her and decided right then to commit a crime, then have the frame of mind to quickly figure out how to frame SA for it. Again, possible, but given the low IQs and poor impulse control, could they have really pulled it off? Especially with the police inadvertently helping them.
Then it's not a huge leap for us to say, well, she's probably told people she's been to the Averys before. If someone outside the compound was stalking her (ex bf, roommate, character we haven't met, or even a total stranger), they could have sort of planned it out, but still would have had to have acted last minute and known the property and comings and goings of other family members. How did no one on that property see or hear absolutely nothing? I can see them not seeing the RAV being up there, but not one of all those people heard screams? Saw a fire down at the quarry? Heard a gunshot? Nothing?
Not to mention other scenarios such as The German or maybe none of the above.
There's really no evidence for anything! I can't figure out which is the most likely scenario. I am thinking the simplest scenario for Colburn finding the vehicle early is that he was on the property and found it. I can't imagine LE set it up so much that they saw her and killed her or found her dead and purposefully framed SA. But who knows? Maybe they did. Makes as much sense as anything, I guess! There are just so many layers and so many people with motive to hurt SA who is not a savory character to begin with, and TH I am afraid has gotten lost in it all, which makes me sad.
I'd say that Steve Avery doing it, is the simplest explanation. It's not nearly as complicated if you don't confine yourself to what the prosecution has said about the crime.
Most don't believe prosecutions narrative of how it went down.
As you said, it's not even a fact that she was killed that night. What real evidence do we have that even says that ?
Jodi's phone call doesn't mean anything imo. If Steve is in the garage and hears the phone ring, he could just go in and answer it, and come right back to the garage. So that aspect is not a big deal to me.
But I also don't think it's complicated to rape her in the house, move her to the garage and kill her via pillow on head (no splatter), move her to the rav4 to transport her to the fire (back it up to firepit), clean garage, move rav4 to location, gather tires or whatever for the fire, and go to bed.
Not saying I believe that's what happened, but that's relatively simple and doesn't take any great complication and doesn't require her to be taken offsite.
It's just a flow of events. Rape, Kill, move body, clean, burn, hide car.
I think Chuck/Earl/Scott/Tadych/ex boyfriend/roommate/stranger would all seem to add complication to the process.
What complicates this case is that they wanted Dassey to be the evidence and so they were using what they coerced out of his mouth to create a narrative that doesn't make alot of sense imo. Trying to frame someone could get very complicated. But it doesn't erase that the crime itself could have been very simple, right ?
I think the simplest explanation above makes sense. Add to my above theory that Dassey helps him clean the garage, not knowing what the blood was from, and then helping him with a bonfire and maybe seeing body parts in the fire.
Again, not saying that's what I believe, because there might be an even simpler explanation with a proper investigation of all these characters.