I am using dynamic symbols for a bunch of icons and when I create a dynamic symbol in black, color editing for individual symbols(which doesn't affect the master symbol) doesn't work. I would like my master symbol to be in black (as it's the most used version)and change its color here and there. But apparently this individual recolor thing with the direct selection tool doesn't work when the symbol has been created in black. Someone can help? would be awesome!
Recolouring of Dynamic symbols does work.
However, in the parent Symbol, I suspect you have chosen a black from the list of greys in the monochrome swatches. Don't do that. It breaks the functionality. Set your black as the black from the list of coloured swatches instead.
If you do that, everything works as expected.
For example, here I have an all-black symbol, with recoloured instances.