First, thank you Jess for your kind comments about my new page and your insights into the sorts of extra-musical concerns that bedevil jazz musicians who have to live complex lives in order to sustain their art.
But as far as the specifics are concerned. Many classical musicians see different scales as part of their repertoire, practicing scales of many sorts. For me the basic ability is to play scales in all keys, but not to think of scales as starting and ending on a particular scale note. I play all 12 major scales from the lowest note on the flute (in the scale) in 3 octaves. Start with 2 octaves if the high notes give you trouble. If you have problems articulating the starting notes, start on middle C (or B or C#) and go down to the bottom before you go up to the top. Always go up and down. You are doing this for fluency, practice until you can play all 12 keys without thinking.
Playing all scales from top to bottom keeps me from thinking of a scale as starting on a particular note, but rather as a key (sequence of notes). I think of minor scales as modifications of the major scale (rather than in terms of relative minors). So once I have the major scale under my fingers, I just lower the 3rd, the 6th the 7th etc. For me the natural minor is just the major scale as are all of the modes. Of course there are the diminished scales, which I just think of as the leading tones to a diminished chord, the whole tone scale as a modification of the melodic minor (major scale with a minor third) and the blues scale just adds a further modification to the major scale (minor 3rd,flat 5th and flat 7).
As far as playing the upper extensions of a chord I am an old bebopper. The central chord is the dominant 7th, which extends along a diminished chord to the 13th. When I was a trombone player in the 60’s we thought of extensions as a half-step substitution, playing e.g. Ab minor (melodic) against a G7. Thinking of the dominant in this ways opens the door for the whole tone scale. Using both of these ideas gets pretty much all of the common hot-licks associated with Charlie Parker.
The best tune for practicing dominant 7th chords is Sweet Georgia Brown since is has four bars on each 7th chord (Jamie Aebersold, 39 has it). Try playing it in as many keys as you can (or even better get one of the Jamie Aebersold volumes that put you through basic changes in all keys, e.g. volumes 3 and 10.
But let’s hear from the rest of you out there. Your ideas are always welcome and will be the key to the success of jazz flute tips.