Node, I have an exercise for you. Make an estimate of the quantity of molten metal that streamed from that tower, and use that to calculate how much thermite would have been required to melt it. Then multiply that up for all the other locations you think that thermite would have been used.
WTC7 – thermite around the bases of the core columns, constrained by sandbags perhaps? Or maybe the transfer trusses, which were a few floors up.