Its obvious there were some well known Israelis and Americans involved in the incident. Most likely only a few people knew the whole plan, and others were told of their role, I'm sure Silverstein was told not to go into work, and allowed workers to work in the buildings at night to install the demolitions.
I doubt there were hijackers, auto pilots of planes. John O'Neil's death is suspect.
I agree with almost all of what you say, with a few caveats:
1- I definitely believe that Silverstein knew something was going to happen, but as to whether he was told not to go to work, or whether he actually had an idea as to what was going to happen that day, that's harder to discern. Personally, I think he knew, and may even have been involved in the planning, atleast when it came to WTC 7, based on the research that I've done. His comments suggest to me that WTC 7 may have actually been an addon to the original plan of demolishing the Twin Towers, a plan which he may have learned of but not been a member of the planners. WTC 7 may have been an attempt for him to cash in personally.
2- As to the "hijackers", I believe atleast some of them were really people, they just didn't hijack anything. Patsies who I think were probably killed once their usefulness was done. Others, upon hearing the news that they were being accused of hijacking planes, loudly protested and even made headlines- the thing is, they were overseas, and this news tended to get buried.
Regarding auto piloted aircraft, I definitely agree. I imagine you have heard of a TV series called "The X Files"? There was a spinoff to that series called "The Lone Gunmen", not too well known. Anyway, the pilot episode was rather interesting. It aired around 6 months before 9/11. Here's a video clip of the episode that highlights some eerie similarities between the episode and what happened 6 months later, especially if you believe that some of the aircraft were being flown by remote control: