I'm 6'2...the pedals are adjustable. For my height I have them set on the furthest setting from the seated position.
I can't claim to have measured the water depth that I have operated in, but the Mirage drive can operate in fairly shallow water. You need water depth greater than the draught of the loaded kayak, obviously. If you are super-shallow, you can just use the paddle or a push-pole. And with the Mirage Drive, the "fins" can lay nearly flat against the hull. You can simply propel yourself in super-shallow water with "short pedal strokes" that don't extend the fins very far down away from the hull.

Yes, the Mirage Drive can be removed, and usually IS removed during transportation to/from the water.