There are so many applications to use your great "pcb sandwich" idea for a display! Are your 0802 LEDs the "side view" type that you just soldered upright? or better yet, can you tell me the manufacturer number of the LED?
I am sorry, I lost source files, I need complete rework this display. You can try reorder this board https://oshpark.com/shared_projects/eL6HGlbh I have not finished arduino code now :(
Neat project! Are you willing to share the updated project files with the 3 separate layers?