re: Apparent and Absolute
Yes, you are right.
As far as visual magnitude Hipparchus started with the number 1 as the brightest and 6 the dimmest when classifying brightness. Later astronomers changed the method as there technology advanced. I don't think 0 Mag. was a starting point but 1 Mag. was and Vega just happened to be 0 Mag. due to the new method. I remember reading something similar to that.
SteveS