Hey Guys, many thanks!
I created some basic geometry of her face from some side reference in other shots for some accuracy and added some simple joints. Tracked mostly to her nose and eyes which took a long time. I only needed the geometry for shadow casting and obscuring certain legs for a short period so it didn't have too be 100% accurate. Usually in a big budget film you may request some head scans which helps a lot but no such luck on this. Once that was pretty close to her movement I added some corrective morphs to the head to have it conform better and added transform deformers on the locations of trackers on her face (these were airbrushed out later) and once more tracked them so I could add some accurate skin deformation and not have legs sliding around. These locators would later be dynamically parented according to where each leg rested. If this sounds insane, it was! 8 legs x 3 spiders equal a lot of animation and keeping their sequence in line. It was all hand keyed BTW.
Lighting, just some trial and error and experience having done lots of these. unfortunately we got no HDRI or reference.
Let me know if you have any other questions!