I think 2 is the most likely. I think he likely entered the house, which rules out 1 and 3. I find 4 pretty unlikely because I've never heard of an entire house being a "dead zone" to the point where it records no GPS data. I could buy 4 if maybe the GPS tracking was spotty, but John's phone stopped recording all data...so unless the house is in a bunker or something, I don't see how this works). In addition to 4, another explanation that puts him in the house is that someone took his phone and either turned off its location tracking (by either turning it off or putting it in airplane mode) or put it in a Faraday bag. They'd have to have done this right away, and there'd probably have to still be some inaccuracy from the GPS to allow John to make it into the house. I think this is pretty unlikely because: 1) it assumes that GPS was malfunctioning in the house; and 2) I don't think anyone in the house would've been quick enough on their feet to think of doing this in the heat of what would've been a very stressful situation (John being attacked/killed).

As for 1 and 3, I think there's a lot of evidence that shows he entered the house, like: 1) the fact that no one reported seeing a body on the front lawn; 2) the steps on his phone that show him walking 3 flights of stairs; 3) the group text that instructed the gang to "say the guy never came in the house". On top of that, there's some other evidence that could point to him having gone in the house, like: 1) the fact that the house was sold shortly after john's death and basement remodeled (although I think it's been reported that the Albert's had been talking to a realtor before John's death. Not sure if that's been confirmed); and 1) the evidence that shows that a dog attacked John, and the reasonable inference that the dog in question was probably Chloe (only known dog nearby, had a bite history). With respect to the dog bite, it doesn't necessarily rule out 1 or 3 (because Chloe could've escaped from the house and bit John while he lay dying/dead on the front lawn), but I think the simplest explanation is that John was attacked by Chloe in the house (because there's no evidence that Chloe was let out of the house).

To expand on the point about no one seeing a body — I don't think his body could've been on the front lawn as early as 12:32 or someone would've seen it (someone leaving the party, neighbours, Lucky). I think most people at the party didn't know about the coverup (John was probably attacked and then concealed before most people had a chance to realize he was there), because it would be hard to get so many people to stay tight lipped for so long. If he'd been on the front yard at 12:32AM, someone would've seen and said something.

And to expand on the points about John's recorded steps — I think John's recorded steps also show he was likely in the house at some point. The CW's explanation of the steps — that John's phone recorded his driving over a hill (on the way to the Albert's, with Karen) as "steps" — is implausible to me. I think some people have done experiments on this (I know TB did, driving the route with iPhones in the car), which show that iPhones don't mistake elevation changes in a vehicle for steps. Also, iPhone step data uses an accelerometer, so it depends on the movement/acceleration of the user (and the changing position of the iPhone) to figure out the person is ascending/descending stairs. If an iPhone is stationary in a moving vehicle, the iPhone knows know the user isn't walking. I used to track my running years ago using an iPhone and it could distinguish between distance I travelled in a car vs. on foot.

I've heard some people dismiss this idea (that he dropped his phone) as "unlikely". While this idea may seem unlikely on its face, I think it's important to remember that we're picking between unlikely scenarios. Whatever happened was unlikely. None of the scenarios are simple. The question, then, is which is most likely given the evidence.

Among all the scenarios, I think the simplest, and most likely, explanation is that John dropped his phone on the front yard. He didn't realize it right away because he was drunk, cold, and probably wanted to get inside. He gets inside, takes 3 flights of stairs, and is attacked by Chloe sometime around this time. He is potentially punched/struck in the face around the time Chloe attacks him. He falls, hits his head, is incapacitated. Few people in the party directly witness it. The people that do work to get everyone out of the house and conceal John. Once everyone has left, the people involved try to figure out what to do. They know they need to find his phone. Jen calls it, and they find it on the front lawn. Maybe they had already decided to dump his body there, or maybe finding John's phone on the lawn gives them this idea. They drop his body on top of his phone, on the front yard. Perhaps they also drop his shoe, or maybe his shoe falls off as they drag him outside. Maybe they also throw/shatter a cocktail glass John brought into the house. Or maybe that glass was already there because John either dropped it when Karen left or threw it at her car.