''Also, how do we account for the many caucasion-type Pharaoh busts and statues, including the very Caucasion looking achitect of the pyramids, Hemiunu, among others? ''

Yes,without a doubt there are caucasoid types,but this is only because of the latter dyansties like the 4th dyansty were located in Lower Egypt. If you notice most of the so called caucasoid statues only look so,because they have intermediate features,meaning some have bublos noses while other have thin lips and pronouced Orgnathism. The paticular statue of Hemnon face was badly damaged by tomb looters and his face was poorly constructed. His eyes were hacked out,and later the rec onstruction was done rather poorly.

Breasted was a racist because he translated the word Neshsi to mean negro,when the word only means riverline Nubian. He also tried to make it seem that the wars between Nubians was racial by trnaslating the word Neshi on the Senwroset III steala.

If you notice though there is a reserve head of a 4th dyansty offical in a mastaba that has been wrongly called Nubian,when it was infact an Egyptian. The Khufu statue seems to have been an Upper Egyptian type as well,but we know that many of the people in his family looked caucasoid. You cannot pick or chose which statues to represent people,because like most mixed people you will get intermediates. Meaning they have some features of both phenotypes. The Saquarra type,as well as the Memphite type can be defined by a person who has bublos nose[negriod feature],but thin lips.