Captain Irrelevant asks:
Yes. Which answers the first question as well.
Yes. And see below.
1. Does external vibration affect the signal in wires and if so how?
2. Why do seemingly inert audio components like solid state amps benefit from being isolated from external vibration?They don't. They benefit from vibration control. There is no such thing as isolation.
3. Is the audio signal In wires itself vibrational?
Yes. Which answers the first question as well.