The best answer I've heard to question of "Were the Egyptian Pharaohs white or black?" was "Yes"
Egypt was multi-ethnic. Sometimes the pharaohs were white, sometimes black. A clear example is the twenty-fifth dynasty (780-685) when Egypt was under control of the Nubians.
Cleopatra, (there were many Cleos, THE Cleopatra commonly referred to was Cleo VII) Egypt's last Pharaoh, was certainly white. She was a Greek of the Ptolemy line. Of her ancestral line, only one remains unclear in ethnicity, her grandmother. And even that is mitigated by the perception of the Ptolemy's and the Greek in general as disdainful of the native Egyptian population.
Thanks for mentioning the period of Greek rule over Egypt. That is an interesting time in history. What a fantastic place Alexandria must have been — this “Greek” city in Africa! It makes me sad to think that a lot of things (writings, inventions, discoveries) were not passed down to us because the records were destroyed.