You are on a good path.
At this point, yes you can give your rig to an animator. There are a bunch of ways you can proceed from there and it just depends on how you want to handle it.
One effective way to deal with this is to build the Ziva rig on the same skeleton bone geo as what you handed off to animators and save that out. At this point on the Ziva rig nothing is moving which is ok. So then you have 2 rigs, an animation rig and a Ziva rig. You can then import the animtion rig with animation and blendshape the Ziva Bones to the animation bones. This way the you have the Ziva rig being controlled by the animation rig. You can attach at any point really, even before you setup Ziva so you have articulated bones to play with.
Alternatively, as you described above, you can cache out the bones from a animation and use that to drive the Ziva rig.
You can, as you suggest, take animation rig and import muscle geo and start setting up Ziva on that file. From there you can save out zBuilder setup and then later re-apply that on a clean scene, or another scene with animation on it. Just be careful to apply it when things are in the 'bind pose' with a runup.
Any questions let us know and we would love to see progress on this!