@inscius While it is true the charts are monochrome, they are still the ones who'd implement the control codes for setting hue etc. (not that I think we should have anything else than monochrome symbols ;)
From a petition news update:
"One of Unicode's representatives told Ginger Parrot:
"Our code charts are actually black-and-white. The color icons used on phones and so forth are supplied by platform vendors, so you would really need to engage with them regarding all issues of how the emoji characters are represented in a color environment.""