The best research I have read demonstrates that the pyramids were built off season by citizens who moved their entire families into well developed communities. According to grafiti this was honorable work done in furtherance of national pride.
Almost like a religious revival....which explains why thousands of people would labor to accomplish a memorial for themselves and their posterity.
If there is evidence of medical care, provisions for daily life and a sense of community - there is less evidence for slavery. Men and women living together would result in childbirth and a need to create a civil outpost.