The Modern Forgery Hypothesis

[Legit]

He used a hodgepodge of influences from dozens of books and pamphlets and real items... changed most of them just a bit so they would not "quite be" that item, all to give a "Kinda-sorta looks like an interesting and colorful old book that will captivate and mystify the masses and rich collectors alike". Sort of like the fake "snake man", the "Cardiff Giant" type thing... and so on...

As you can see with my attempt to disprove the armadillo theory, it's really hard to prove a negative.  Regardless of how unlikely it is, there's still a sliver of room to say, well maybe the forger happened to do it exactly like that with the proposed intent.

You can take this as far as you like - I could claim that a star that is close to a line is meant to be a streetlight.  Nobody can prove me wrong.  Nobody can disprove my suspicion of the intent behind any of the amorphous illustrations.

Any good theory should have an invalidation point.  With deciphering the text, a high number of untranslatable words invalidates a theory.  The C14 dating invalidates dates earlier than the 15th century for the manuscript.

If it's a forgery, it was a monumental effort.  Buy an old bookstore to get old vellum.  Get lucky the old blank vellum is actually from the 15th century.  Come up with a recipe for iron gall ink that would stand up to future chemical analysis.  With all of the structure of the language, the internal complexity and huge numbers of ties to documents of the period, and not just common ones, but obscure hard to find correlations.  Then to process the document to create wear with layers upon layers of details. Somehow make hundreds of thoughtful additions like the faint substitution decryption attempt giving the impression of a document that's been used across centuries.  The Tepenecz signature. Then forging and matching signatures of the letters and matching the handwriting of the scribes on the Marci letters and the rest of the provenance. Get lucky so it stands up to multispectral imaging.

But none of this can disprove a suspicion no matter how unlikely it is.  What would invalidate your theory?