Respecting your thinking, I disagree.
1) Yes I think there was time, because remember no one was looking for LS at 4:00am, or 4:30, or 5:00 or 6:00... it was hours later. He/They/whomever had several hours. In addition to that, the body could have been placed temporarily in one location, and them permanently buried elsewhere.
2) There are many graves out there. How many of them do you see opened? It is one of the last places anyone is going to look for a body.
In an above ground Mausoleum, people do not regularly check their loved ones corpse. This is far too gruesome for most people to do. So, no this sort of doubling up could go unnoticed for a long long time. I've been to cemetaries and seen some rather amazing things. I've seen fresh graves, that have just been covered, these are easy to spot. digging down a few feet through loose soil would not be difficult. putting the soil back and even the cemetary caretakers would not think anything strange. I've also seen fresh holes dug with equipment in place to lower a coffin just before a burial. Note that Jewish tradition is to have a quick burial and the actual funeral 1 year later. It's a little more tricky, but possible for someone to get into one of these deep holes and dig even deeper and bury a body which would then later have a coffin lowered on top and then filled with soil. Again, this might not be discovered for over 100 years.
But then I'll tell you something else I've seen. I've seen old cemetaries from over 100 years ago get bulldozed and no one was looking at what was being turned over in the soil. Many years ago I was playing tennis at a university that borders a cemetary. The ball went over the fence and my opponent insisted we retrieve it. this is one of those areas that had recently been bulldozed due to some changes in the boundary. In looking for the ball, we found parts of old coffins laying right on top of the ground, and large sections of a human skull. So... point here... if you think cemetaries have 24 hr surveillance and really astute people working in them you are mistaken.
3) I did lean towards an outright OD or OD + Alcohol + possible health conditions BEFORE I saw the Video in June of the 2 PI's describing LS slamming into the concrete and face down into the gravel lot. The changed my view to that she was also suffering from serious head injuries.
So, 4th person, mystery person, is definitely plausible and various theories still unbroken. But... I disagree that you think LE would have run that down by now. Clever people, paranoid people, rich people, local people, all could have pulled this off in the various scenarios.
Recently someone proved that JR did not have his vehicle on the night LS vanished. And that strongly supports the 4th person theory.
And let me flip this around to you. If you think it's so unlikely that a pro disposed of LS, or that JR and pals were not capable of a respectful burial given the several hours they had, then how do you think it went down?
