Quoting myself again for the 3rd time:

In the art of rationality there is a discipline of closeness-to-the-issue - trying to observe evidence that is as near to the original question as possible, so that it screens off as many other arguments as possible.

Maybe I should have emphasized "screens off as many other arguments as possible". You have a made a list of such arguments/questions. Mind you, they are all worth investigating but I'm screening them off the key question, namely: "Were explosives planted in WTC7?" or "What caused WTC7 to collapse"(hat tip to Morendil).

Look at the following video: http://www.youtube.com/watch?v=79sJ1bMR6VQ

Do you agree that this was a controlled demolition? Do you agree that you can make this statement without having any of your listed questions answered? If yes, you can then proceed to ask your previous list of questions:

• How much explosive charge would it take to cause the failure observed?
• Where would it have to be installed?
• How many hours would that take, and how many workers?
• How many people would have to be displaced so as not to witness the building being prepared to blow?
• Where did the explosives come from?
• Who paid for them?
• Who delivered them, and to whom, where?
• Why didn't the fire interfere with the operation of the explosives?
• How much noise would the explosives make?
• How quickly would the building collapse after the explosion?