I would need to know how to keep fondant from craking when dark/intense colors have to be added. Each time when I color my MMF with black gel, or red or other intense color, the MMF changes its consistency making it very hard to work with.

This is the exact reason so many of us buy the dark colors. The blacks and reds take a LOT of color and the end results are usually a very hard to work with MMF. Not fun I've given in to the easily purchased colored Satin Ice. Heck I even buy white to have on hand for figurines, bows, etc. I hate gumpaste lol. I hope someone has an answer to save all the fondant you've colored! Other than adding shortening I'm of no help! Best wishes to finding a solution