WOW...... for sure there has to be some chain yanking going on...funny how someone can join CC one day and the very next day start a discussion that gets everyone hot under the collar.
I think you need more powdered sugar, and let it rest overnight. You should keep adding th ePS until it is no longer sticky, then wrap and let sit overnight.
To make black I use wilton gels. Equal amounts of red, blue and green. I did this to color white fondant (mmf) black. It's in my pics (bee hive) - Works great!