I wrote up 99% of this idea in stupid font tricks, but I was thinking that where Unicode has a lot of man/woman/person emoji, and five shades of skin tone on top of that, the generic case could be hijacked to emit a random variation based on a hash of the surrounding text, and groups of uniformly generic people would become a diverse mix of all that Unicode has to offer at that codepoint.

I think Google’s Noto Emoji font is distributed in a form that might let me hack that into it, but I have to do some fiddling to see.

And of course, if I’m hashing the surrounding context I’m not restricted to cycling between existing glyphs. I can also add ones for which there is no specific codepoint.