"I'm going to go out on a limb here on the third point and give the following hypothesis: the minimum wage *might* have had an effect of crowding out black labor (since black workers obviously typically made less), but this effect would have been minimal at best, and any business owner would have been firmly against something that would crowd out black labor. I say this by analogy to something similar that happened in South Africa during the early 60s. They passed a law that required wages for black workers to be set lower than wages for white workers. The result was a surge in employment for black workers (and remember, this is South Africa in the 60s, one of the most racist environments in history). Why? Because regardless of anyone's built-in prejudices, the fact was that black labor was cheaper, and therefore profits were higher. The law was repealed very quickly, and other, more effective ways of suppressing the black population were implemented.
So I am inclined to believe that, while it's feasible that there may have been racist intentions behind early minimum wage legislation, any effects that disproportionately happened to black workers would have been absolutely DWARFED by the negative effects of the general racism present in society as a whole. This is not an easy hypothesis to test, but I believe it could be done."
I think this is dead on. Anyone that knows anything about how old school racial caste systems worked in the South knows that white power brokers didn't want blacks unemployed. That's the last thing they wanted. Hell, for a couple hundred years these guys imposed a maximum wage of... errrr... zero. Even in the twentieth century, their goal was not a bunch of unemployed black people.
The goal of Southern racism was (and is) to keep blacks in "their place", not to keep them out of work.