I enjoy the sympathetic objects and the tethering mechanics. I know that generating roll tables is difficult, but the use of d4 tables for generating sympathetic objects appears to stray from the expectations of FIST as a wholly d6-based system. However, these are a great starting point and could be further expanded whenever further ideas come to mind to fill the tables out.
I have friends who are very much into Control, SCP, etc and think this adventure would 100% be their jam. Awesome stuff!