Any idea if the Lazarus reflex* can happen to freshly-decapitated bodies? Or maybe to dead bodies that recently experienced other head trauma?

I think it would make sense. Having no head looks similar to brain-death or brain-stem-failure; there was a report that the condition of a decapitated body seems remarkably undisturbed, which sounds similar to the condition of an otherwise-living body being taken off the respirator. And this reflex is coming from the spine anyway.

*See en.wikipedia.org/wiki/Lazarus_sign
This is a sort-of postmortem reflex in which the arms flex at the elbow, rise, then come to rest on the chest. I just like the idea of a dead, naked woman covering her breasts as if she's embarrassed, or maybe embracing someone as he's doing her.