I don't know much about the conspiracy theories there are around 9/11, so i can't comment on whether or not i believe them.
From one of the links you provided (http://www.popularmechanics.com/technology/design/a3524/4278874/), the report said that World Trade Center 7 did collapse, 7 hrs after the fall of Towers 1 and 2. But what it also said was that the cause of the collapse was fire - burning of its office furniture, as the debris from Towers 1 and 2 close by "ignited fires on at least 10 floors of WTC 7". The cause of fire was not from explosives.
Display Picture from Rita et Machin