Hi James, I'm suspecting what you said in No2, to be the case, even when starting a ziva setup from scratch I'm experiencing the same problem, I've had an awful lot of problems caching ziva stuff out to alembic, usually what I do is cache out the animation on the bones, then bring the alembic cache back into maya, then combine all the bones of the alembic cache, and that doesn't always behave itself, sometimes the whole mesh loses it shader, and disappears, all sorts of weird stuff.
Right now I've managed to combine it, and re-writing it out as a single geometry so I can bring it in as one piece for ziva to convert it to a bone, rather than a hundred separate pieces, hopefully, this might work better.
Difficult to send a minimal scene, the alembic cache is huge.
Beckons the thought perhaps you guys could write a better caching system for writing out the geometry from ziva.
Even better a cache that you could write out, bring back in, perform sculpt fixes, and re-write out a cache, would be amazing, food for thought🙂