Other turboprops, like the PT6 described before, use a more direct drive for the propeller; via a turbine in the exhaust stream.
Most of my experience with engines is with pure jets; I was amazed at how much more complex the power package became when you bolted a propeller on the front!
I don't know if a PT 6 is more direct drive for the prop. It's a "free turbine" design. After the last power turbine to run the compressor section there is an additional power turbine to run the propeller. After this there is an a gear box for the propeller. We can adjust our prop speed independant of engine N1 rpm (think engine core speed). We have a torque guage for each engine telling us how many ft/lbs we are putting through the prop. RPM range is 1400 to 1750 for the props. In this way the PT6 performs like a more complicated piston engine with regards of how you operate it.
We also actually have a gap between the last compressor power turbine and the output power turbine instead of a shaft that just spins inside another.
On a PT-6 you feather the prop when you shut the engine down, and it's not harmful to feather in flight or on the ground (providing you aren't trying to power the engine!)
What happens is that now at idle you are running torque to the prop instead of almost none to just turn it at flat pitch at a relatively low speed.
Wehn I was doing my flight training in the 1900 we feathered props in flight (with the engine running) to more accurately simulate single engine manuevers. You shouldn't do that with a piston engine, however! You probobly can't do it on a herc either from the sound of it.
the caravan has the reverse thrust triggers on the throttle because as you force the oil into the prop hub to push the blades to a negative angle you must in crease the engine speed so you do not over temp the engine it is a reverse flow engine which means the air is sucked in the back of the engine and pushed through to the front same as a king air. to answer the question the prop lever only controls prop rpm and the mixture controls engine speed on the ground hi and low/ fuel metering for another word. It is agreat airplane to fly cruise at 160kts. downhill at 175kts to the MM and stop by the first taxi way. by the way it stalls dirty at 45kts. waaaaaaahooooo!!!!!!
The 1900 has a PT-6 as well (just a different version with more turbines and more power output), our reversers are detents on the power levers just like a standard jet. The caravan has triggers because cessna decided to do it that way.

Here's what our power levers do: You have Idle, normally called "flight idle" Forward is more power like conventional. Behind idle you have a detent (lift the lievers up), and go back into "ground fine." Ground fine starts at a flatter than normal pitch and goes back into a slight reverse. Then you hit another detent to lift past to get to "reverse" range. Now, you aren't in full reverse yet, but at this point rpms start coming up and the prop goes further back in pitch until you get full reverse.
There is no "mixture" on a turbine. The condition lever just controls idle speed and fuel cuttoff (to shut down). Turbine engines control power output by fuel flow, just like a diesel engine. Increasing fuel increases power, decreasing decreases it. BUT, your throttle on a turbine doesn't control fuel flow. It controls N1 rpm governor setting. The governor adjusts fuel flow on its own to keep the RPMs there. Mechanical injection diesels actually use the same method. Mashing the throttle on one doesn't increase fuel directly, just governor RPM setting.

-Ryan