A1: None of these components calculate the RMS value of an input signal. If you add a "Square root data" component after "PeakSq" component you may be getting a good appoximation of the RMS value.
A2: The output of these components is the alpha filtered value of the absolute input value. This is akin to a moving average. The context menu of each component has a help option which shows the detailed flow diagram in the Z-domain. Please clarify what you mean with the second part of your question.
A3: Yes, the amplitude is a run time parameter. You can change the Amplitude by writing to the fourth word (offset 12 bytes) within the component interface address. 0x00000000 = 0 (mute), 0x40000000 = 1 (full volume).