The last paragraph gives the interpretation as porosity below the current surface layers, and a rebound with basaltic origin at depth I would presume cause a 'scoria/cinder' type effect, with water present in the true bowl of a crater. Subsequent layering of impact clays from liquefaction might bury the porosity layer. Does my suggestion seem possible to you?
Why the presumption of a massive removal process? The inner rim slopes show large scale semi-fluid patterns at places rather than sedimentary fine layered residuals, a weather changing pattern would fit the suggestion of a post impact lake without infilling, and the erosion of the down flows you displayed come from the upper layers, with a major evacuation vertically in the mid-section of the primary 'mountain'.
The concentration on a massive long lived lake, would be timed after the 'dike swarm' details from regional volcanic sources, and the dikes penetrate the mountain in satellite images. The crater and mountain/cone would have to be much older than the regional volcanic sources.
The surface layers appear not horizontal in bulk.
Vertical small structures match the common vertical erosion removal at larger scale in the layers passed.
Water and basalt interaction during the impact possibly could result in porosity, but the bottom of layers seen by Curiosity show a pitted, removal process is real.
Why would porosity not be a subsurface activity, rather than a dry assembly of porous grains?
Why would the wind altered layering at lower elevation, show any similarity to the upper slopes and the density of the core of the mountain?
Why would a crater cone be a lake deposit in bulk?