That's the thing. I have yet to see anything that suggests the Saints saw Baun as possible replacement to Davis. Have you? Besides articles from the draft, which you have to admit predates his time in a Saints uniform, has there been any indications of him competing at MLB? A training camp report? A quote?
This rather feels like trying to discount evidence that doesn't support a particular hypothesis, by adding new criteria for what constitutes evidence. I can't say I agree with it.