Writing the purpose above the draft is the step I'd underline too—it keeps the diagram from quietly turning into a biography nobody asked for. The legend point matters just as much: a plain line between Alex and Morgan tells a viewer nothing on its own. Keeping a separate version for anything close to real people, with invented names in public versions, seems like the right habit. I'd add that labeling which episode a draft covers helps when relationships shift, since last week's coworkers can read as something else if the notes go stale.
