I do not buy the "specific set of rules" you say is needed to be followed when doing EGA. I never thought about it that way, ever. If you have a decent knowledge off colour theory then you will figure out which colours work together in ANY given palette.
One exception I can think off would be something like PAL blending, which occurs if 2 colours have the same luma and are displayed on a proper CRT monitor with a PAL signal. Those 2 colours will make a totally new colour if alternated horizontally, because of how the hardware works and the PAL signal is encoded. This is something that works on the C64 and maybe on other Commodore 8 bits as well. This could be called a technique, but it is not C64 technique.
And about blending being jargon, I think everyone understands what blending means. If you tell someone about colours blending in natural media such as oils, they will get it, if you tell someone how printing is done with dots grids of a bunch of colours and that the colours to a degree blend visually, they will get it. If you stop assuming people will be confused by such terms, and treat people like intelligent human beings, you will get further in what you are trying to do. Art is not quantum physics or anything like that. The concepts of colour blending and such on an application level are not very hard to understand.
I think that effective instruction has a lot to do with looking outside of pixelart, which has a very tiny insular set of specific things which are kinda unique to it, such as manual antialiasing and dither (dither already is borderline as you could dither in non pixelart too). Colour theory, perspective, anatomy, composition. This is the kinda stuff people should learn. I believe that any artist who has solid classical training could be made into a superb pixelartist in a matter of months if given the right instructions or given good self-motivation.