Since the core of WTC 1 was the first to begin giving way...
This part of the story is obviously true but if it come to "the core collapsed first" then you become a delusional twoofer because THE REPORT has a very different way to interpret what happened. ...or did I missed something?
..., wouldn't a valid explanation be that those ejections were the result of partial floor collapses...
Besides the hundreds of unexplainable coincidences, yes, it would be if you consider that a part of the 96th floor fell on the 95th floor and a part of the 93rd floor fell on the 92nd floor starting a raging fire that needed 10 minutes to burn from the middle of the north face around the NW corner and south to the SW corner. ...while a raging fire at 95 started too.
Both areas have to fall at the very same moment but do not pancake down from 96 to 92. That areas have to be huge at both floors to expand enough pressure through the entire floor area. These huge areas have to fall inside the core, just to explain the smoke pattern e.g. ejected opposite the hallway through the core. Well, the core area is that area with the most columns and the smallest areas without columns. There is a certain probability that more than one column must be involved. On the other hand, the core area had a lot of shafts and just little furniture. That area lacks of fuel to explain a long lasting inferno that e.g. drops a floor without fire below and without damage to the fire proofing below especially inside the core.
Coincidentally these partial collapses have to occur at the floors of core column connections but may not cause some suction (like above the falling WTC7 penthouse) but of course the air that was blown out of the windows at 95 and 92 must somewhere else enter the building.
The falling area could suck down the air trough open shafts. So the suction might be widely distributed and hardly visible but there are the same shafts below the falling area.
...or the beginning of movement within the building interior immediately before the main collapse started? The ejecta simply looks like smoke, which doesn't appear particularly strange to me....
That ejecta (as far as visible from the roof of CNN) is mostly smoke. Without the smoke we wouldn't have noticed that pressure pulse at all. Between the lines you seemingly ask for suspicious characteristics of squibs. As I mentioned above, even if there were blasts of high explosives it wouldn't be very probable that we would see any sign of it. The sound is a different problem but comparable squibs reaching about 10 meters with little of bright smoke. A blast 20-30 meters away from the exterior walls in a smoke filled space and shielded by walls and elevator banks would probably look like what we see.
You can compare it even with the appearance of the dust fountains. These fountains started "invisible" but sometimes they blew out huge chunks of debris. ...and some moments later these spots of overpressure started to blow out massive amounts of fine bright dust. Thats the time we usually see them first.
It could be the beginning of the movement within the building interior if there is any good explanation either for
- core columns breaking at both connections simultaneously at zero degree tilting or
- two core areas collapsed at the very same time for any reason while the ceiling of 92 has to collapse just due to movement and without visible fire ejecting a lot of smoke. ...smoke?