Jim, just for terms, I normally call ‘the complete composition’ a score.

Jazz and some pop leadsheets normally do show chords.

Leadsheets can show more than one part. They often show two parts on a single staff, plus percussion cues above it. On some of my leadsheets, I use two staves and put the counterpoint, bass line and/or rhythm section parts on the second staff, when doing so on one stave would be cluttered. It’s even possible to have a leadsheet be mostly a single staff but add a second for specific sections. In other words, you write it in whatever way gets the job done. For another example, in a big band chart I will often create a reduction on one or two staves that has the important entrances of each section so I can conduct. It’s easier than reading the full score.

One good thing about notation: it’s hard to be wrong. The standards are very old. The newer notation uses fonts and chord symbols that are not standardized. This is why BIAB gives you many options. I just take a moment and explain what I’m doing and everyone is fine with it. Someone else’s chart may look quite different and that’s fine, too.

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