ok
3 rd one
it is because not everyone sharpness blade same. there is a lot reasons could be factor's. pressure, strokes etc etc.
about 4rth
Sorry
i am not agree with You.
Natural hones will act differentley but that doesn't mean example 1 escher will act as a 30000 grit and next one will be 2000 grit,there is not such a gap amoung them.
could act example 20000 next will be 18000 etc . not so much caps.
hope this helps