mea culpa
pickup note is A flat and tonic is D flat.God bless Bill Strayhorn.
My college jazz band director was the late Bob Goebert,high note trumpet man for the Harry James Big Band.I was a rocker and he dragged me back into the 40s.
As far as the guitar's function in the band,that varies with the era.30s swing (Satin Doll,Stompin at the Savoy)requires the guitar to strum every beat on the beat,a holdover from the days when the banjo was the piano's comp buddy instead of the guitar.
Postwar swing (Chattanooga Cho Cho,In The Mood) has the guitar "punching" the chords.
Bop is where the guitar was finally allowed to be a melody voice (Charlie Christian,Wes Montgomery)
Latin,East Coast Cool,Fusion, it goes on and on style after style to that abomination known as "smooth jazz".
Watermellon Man is a great choice,or other tunes like On Green Dolphin Street,Equinox,My Favorite Things,My Funny Valentine....
Sorry,its easy to get carried away.
Tom