I haven't done much reading on Huxley so I wouldn't know his stance but I assume you are right because such statements were common to 18th 19th century European anthropologists.
I do disagree wtih you on the issue of Ethiopians, Somalis and Erytreans for they are, on the whole mixed with Arabs. THis is a historical fact that goes back at least 3000 years. Since I was a kid, I did have several Ethiopian friends and while many were "pure" black, others clearly showed that they had mixed with Arabs. One such individual explained to me that Arabs and Africans had exchanged genes for thousands of years through trade along the Red Sea. It i snot difficult even for the average untrained eye to see the similarities in facial features between some east Africans and Middle Eastern Semitic populations.