As for magic systems, the subdivision in "classes" is always forced.
There are actually only two aspect to shadow powers: emission and manipulation. Emission determine the amount and strength of the soot you produce, manipulation determine how finely and accurately you can control the soot you produce. Everything else is just imagination.
You instinctively awaken a power related to your disposition, but once you realize you can manipulate soot, there is no reason why you can't reproduce ANY other power...