What is the order of authority within canon?

Obviously George and the films/scripts are firmly at the top, but where do the following rank in terms of significance when they make a statement:

Leland Chee.
Pablo Hidalgo.
Daniel Wallace.
Ryder Windham.
Your average author (e.g. Drew Williams, Matthew Stover, Sean Stewart).

Second question: If one of these sub-Lucas/films/scripts figures made a statement on character power levels, are they automatically accepted as being the canon answer? 

I really don't understand half of the crap with author/executive statements so hoping someone can clear this up for me.

i think that canonization can be changed depending on a few things- retconning, amount of counter evidence, and time as in, new info is released.

"Drew Williams"

On topic, none of them have authority on power levels unless they're speaking on Lucas's behalf, unless you accept authorial intent, which I don't.