Following the 2011 Guidelines (for both Nemeth and EBAE) and incorporating the UEB Technical Guidelines (4.4.2 first bullet), you would omit the grade 1 indicator for all capital letters and include it for all lowercase letters (including a, I, and o).
Note: If there is no reason to show the diagram within Nemeth switch indicators…keep it in UEB. (The letters on your example of a triangle are simply labels, not mathematical expressions.)
Betty