It's now February 2019, a little more than one year since this archive was created. A writer colleague who is originally a UK citizen shared a question: "Who was the first person of color to be knighted by a British monarch?" Geoff amended the Quora question with an additional investigational request.
Well, I'm into research. There were two responses that could be considered responsive. The first related to Sir William Conrad Reeves via Wikipedia. However, that may not be responsive to the question.
The second item discovered related to not people of color generally but specifically Africans.
What about the first knighted in the 17th Century? If you have additional information, please do share it.