Here's a pose test with my latest version of the output. Clearly not quite there yet, but also not entirely terrible, I think. Technical note #1: in order to keep her lingerie (that Wikipedia calls a "corset teddy"; let me know if you have a better word for it) from falling off her you-know-what's, I originally put the whole bust and a corresponding strip in the back into the constrained group, but that made it look awfully stiff. So, now it's only the top "hem" that's constrained, with the remaining fabric being free to flow on top of it. I think the general strategy is quite promising: saw a piece underneath the top fabric that's close to the skin and constrained to it, as if one was using actual tape. That will only constrain the top fabric at the respective seams rather than across whole polygons like with my previous method.

-- I'm not mad at you, just Westphalian.