1. Probably acts as the project manager for an embedded project,
2,3 May be one in the same, it depends on the definition of "embedded software". An example might be development kits. If "embedded software" is also defined as firmware, then that's they guy writing firmware for the device. The definition has blurred because of less masked ROM type stuff. The guys that built the dsconverter box for the digital TV conversion in the US must have goofed and had to do a part of the design outside the chip. Those kind of firmware mistakes are expensive.
Firmware is ating much more like software nowdays being reprogrammable.
4. test engineer. Tries to break stuff or has to devise ways of production testing.