Q.Gardening
I would like to install a mirror over the sparse growth side of this wall (to the left of the topiary). The mirror would not be installed directly onto the wall, but onto wooden blocks. These would be then installed on the wall by moving aside the stems of the creeping fig. All in all, there would be about a 2″ gap between the cinder block wall and the back of the mirror. The installation would not impede the growth of the plant. The concern that I have is that I would be blocking the stems from sunlight. Do the stems need sunlight? The foliage would not be covered. Please see photos.

Certified GKH Gardening Expert
No, the stems don't need sunlight, so your plan should work fine as long as the leaves aren't covered.