This seems like a combat encounter where the PCs have to find and fight a demon, but it's a much more compelling and interesting mystery and social encounter. I like all the different approaches and how each solution offers distinct pros and cons. There's lots of clues that if left uncovered could come back to bite the PCs, which is always fun.
The table could use some clarity. I thought it was 10 items but it's really describing 5 bas-reliefs and their meaning. Overall, with some polishing plus a font rework, and you've got yourself a banger of an adventure to drop into an ongoing campaign or get players pulled into a god-demon war.