my suggestion about the author of MV

[Anton]

Are there significant facts to believe that the author lived in the 15th century and did not use drawings from books in 16th (clothing)?

I'd say there are no significant grounds to believe the contrary. That's what the Ockham's razor is about: "frustra fit per plura quod potest fieri per pauciora".

If one presents such grounds by unveiling some new facts in confirmation or, perhaps, by revealing that the "15th c theory" has some inherent contradictions, then, of course, that would be quite a different thing.