> any two emojis should be combinable

That's literally what emoji kitchen is.

> They should support the "color combining code" with a 3 byte sequence so you can specify ANY of the 16,777,216 color variations.

Why stop there... we have 10-bit color and beyond now. Give me display-p3 (https://webkit.org/blog/10042/wide-gamut-color-in-css-with-d...)