The first question which comes to mind looking at the ground is were there two paths up the escarpment, one ramp and one processional causeway.
Firstly, many thanks for your generous photographic contribution to the discussion. It's rather amazing that no one has provided any images of such quality on this section of the plateau before on any forum of which I am aware. Much appreciated.
As you are probably aware, I have had reservations about the placement of the Eastern Boat Pit with respect to the Causeway.
In presenting the image below, I asked Thanos the question that, whether or not, the blocks and detritus to the right of Reisner were, in fact, part of the Causeway.
In the 1862 image below, the remains of the Causeway can be seen. However, upon careful examination, it does not appear to be contiguous with the excavated pathway from the basalt platform ("Mortuary Temple"). It appears to be a continuation of the blocks in your recent images.
When added to Dune's aerial shots, this could possibly be so.
Therefore, my thoughts are that you have considerable support in your contention that there were two constructions.
A caveat - purely personal - is that neither may have been for the purpose of the transport of heavy materials. The NW entry point still seems to be the most practical for that purpose.
The accepted causeway may have been for a solar alignment and the "new" causeway may have been a Processional Way. This could negate any dogleg construction, which has always bothered me.