3) neither plane undergoes significant deceleration upon impact [this was quoted from Humint's analysis]
Just one quibble so far:
Obviously the aircraft in the second video example (#2) above decelerates! The aircraft speed goes to zero. That is a huge deceleration. In fact that is 100% deceleration!
A force must be applied for any object to stop moving. Otherwise the tendency of the object is to continue at whatever speed it is traveling. That is inertia. And the energy (of the force) implied in that slow-down, the change (delta) between the speed of 500-whatever mph and zero mph, is what breaks up the real aircraft in the second example.
In contrast, we know in the first example, the "aircraft" is not real.
Because "it" hits an immovable (relatively) object and not only does it not stop, but it does not slow down.
What is implied in that fact?
That there is no force applied, which clearly insinuates a depicted situation which is not real, considering that what you are supposed to be looking at is an aircraft traveling at top speed hitting what was one of the most massive man-made object on planet Earth.
"Reasoning" along the lines of the unreal situation...if there is such a thing...("reasoning" rather than reasoning)......
If there is no force applied, there is no reason for the "aircraft" to break up.
There is also, similarly, no reason for "it" to slow down nor any reason for there to be a hole in the building......
unless that "building" were made of smoke, butter, cellophane or pixels.
I forgot: if it were made of butter or cellophane, there would be a hole of some kind made. Even with a smoke building, you might make a hole of some kind with a projectile. Unless the "plane" were a ghost.
Obviously the hole in the actual building (not the image of an hole) was made by something other than the image of a plane - and in any case the actual hole was not large enough for a 767.