PPL(H) theory credit towards PPL(A)
Answer 1)
Things happen faster in a fixed wing, purely because of airspeed. Because of the faster speed, nav errors (off-track errors) are less in a fixed wing if dead reckoning. Conversely, in a rotary wing, you can pull up and have a think. Apart from those obvious little gems, nav is nav...
Answers 2 & 3)
No idea - these abbreviations mean nothing to me, I'm afraid. We don't use these in Oz.