So after much deliberation, I decided I’d fix the head indent myself. Happy to report that the fix went very smoothly.
I believe I was correct about the foam collapsing and thus being the cause of the indent. If anyone is familiar with polyfoam you’ll be familiar with that issue.
As far as the actual process, I’d highly recommend Adam Savage’s video for the body deconstruction.
Once the body was open, I removed the head and used a fresh exacto blade to very carefully open the bottom hole a little wider. The foam was rigid, but rather soft maybe a 3 or 4lb foam? In my case, it was very clear by the appearance, whatever it was, it was mixed incorrectly. It being rigid meant I wouldn’t be able to just pick it out like I’d hoped. Turned to the trusty Dremel with a sanding drum. It cuts right through the foam like butter, but light contact with the vinyl doesn’t do much to harm it. I dremeled a decent cylinder all the way down to the top of the head. This took maybe 5 minutes at most. I bagged the head with a rubber band around the bottom to keep it nice and clean.
I blew all the foam dust out of the head with my shop compressor, and added a little bit of cotton padding. After a few seconds very gently heating it under a heat gun (be very careful of the hair) I used a wooden dowel against the padding to push the head into place. Hot water may have been a better way to do this but I was worried about the paint.
I held it until it cooled down and then packed the rest of the head very tightly with the cotton. It seems to be staying in place on its own, but I may make a little fabric cover and glue it down to the vinyl just to keep everything in place.
Just waiting on the armature wire and then I can finish this up. Apologies I didn’t take any photos through the steps. I will be sure to take some nice ones at the end of the process when he’s all back together.