My first instinct was right, the chapel room is a map!
The Talocan Ten are not idols, nor are they gatekeepers for a treasure room. They do not represent star systems either. Rather, Reinhart Novan's research shows that they represent ten complexes in Aphi, with a set of Talocan acceleration gates at each complex. And the cogwheels are not keys for these gates, but pointers to help navigate the map. The statues help place the cogwheels in the right direction, indicating a spatial orientation of the complexes with respect to each other.
Let the treasure hunters be damned, this leads to historical information rather than gold: a hidden Takmahl space cathedral! I haven't heard about the Takmahl constructing space cathedrals, so this one could hold valuable artifacts and relics stolen from Athra!
