Budu and the enforcers are all not-of-any existing race, and he IS a major character.
Nan d'Araignee is certainly a major character, as are:
Suleyman - African
Latif - African
Sarah (Sarai) - African
Nefer - African
Nicholas/Edward/Alec, while 'somewhat' Caucasian are Recombinants made with DNA from 'Homo crewkernensis'
I think more than most science fiction authors, Baker went out of her way to portray many characters of many different types, nationalities, backgrounds, etc.