Jazz is mainly harmnized using 7th, 9th, 11th, & 13th chords. The harmonies are constructed mainly from the major and minor (3 forms) scales. All of your questions require complex answers and I tip my hat to Bardsley for offering an excellent response.

I'll give you the names of some great jazz guitarists to look into, many of them who are living have great websites that you can check out for answers to your questions;

Jimmy Bruno (www.jimmybruno.com / I highly reccomend it)
Pat Martino Joe Pass Wes Montgomery John Scofield
Mike Stern George Benson Barney Kessel Larry Carlton

just to name a few