Your discussion of “concrete and novel” is right on. This standard goes far beyond the congressional intent behind the copyright statute. Congress used Novelty as a standard in Patent law… if they’d intended it also for copyrights, they’d have been explicit about it.

Also… it’s Justice Potter Stewart, not Stewart Potter.

The conclusions drawn are correct, but in practice, (at least here in Hollywood) Agents don’t ever sign confidentiality agreements… after all, it’s their job to get the material OUT, not keep it secret.

The usual practice in making submissions is to establish the paper trail, as you’ve suggested, even if it’s one-directional.

Finally, many studios, production companies, etc, will ask for a “submission release”… In my practice, I always advise my clients Against signing such documents… they’re essentially a ‘license to steal’, and always a big mistake.