Hmm... I know nothing about "micro" pigs but do know that BLACK is dominant so my guess would be that if you breed black to black you will only get black.
In the past we have bred Large Blacks to GOS (Gloucesertshire Old Spots - white with black spots) & all the piglets come out black with maybe white feet & pink noses! When we have bred Large Blacks to Red Wattles, it was on the rare occasion that we would get a red piglet. Most were solid black or black with red horizontal stripes that fade as they age.