Not wanting to come off as a self-proclaimed expert here, but I have been using, and been exposed to, nearly every type, weave, thickness and quality of woolen blanket that is readily available. Aside from animal hides, wool blankets are the only historically acceptable bedding for my other hobby.
Because of this, I am here to say that the thickness of blankets runs the gamut from hand-woven and very thick, to military surplus from warmer countries and hence very thin. The drape and hang evident in the pics is very much possible with the thinner blankets. Although totally wrong color-wise, an old US surplus blanket would provide that EXACT same drape/hang/crease.
I am STILL on the case, and confident I can find a suitable answer to the cape mystery. I just need to wait until Spring, when the gatherings start again.