The Book Switch Theory

[ReneZ]

1) Wilfrid Voynich said in his 1921 lecture to the College of Physicians in Philadelphia that he found the Marci letter "attached" to the front cover of the VMS.  Is there any other documented reference to the Marci Letter being colocated with (even if not actually attached to) the VMS from PRIOR to that 1921 lecture?. 

There are some 1915 and 1918 newspaper reports where the letter is called a 'flyleaf' and some of the names in the letter are quoted. I hesitate to associate this to a communications error or just bad journalism. Undoubtedly, there are many more newspaper reports that have not been found (online) yet, but they will tend to copy each other.

2) Likewise, in that same lecture, Wilfrid Voynich described the signature of "Jacobus de Tepenecz" found on folio f1r. (There are variations of the spelling - I usually use "Tepenec".) Is there any other documented reference to the presence of this signature PRIOR to the 1921 lecture?

There is a photo in the Beinecke libary that was taken before the chemicals were applied, in which vague traces of parts of the signature can be seen. Rich should have this on his web site. 

3. Is there any other example of Hořčický's signature (post 1608 after his enoblement with the de Tepenec title) that actually matches the form found in the VMS? 

Yes, one in a book preserved in the Czech National Library, that was located by Andreas Sulzer in 2007 or 2008, as the scanned index card was found in a Google search. Stolfi will remember that we manually searched through these cards in 1999 (or 2000?) but did not find this one.

   

4. (alternative to the above question...) Can someone point to multiple examples of his signature that show variants of form such that "Jacobus de Tepenecz" would be one of his natural variants and and not a unique and distinct outlier?

This is an ex libris. There are not many, most from before 1608. Most of his known signatures are indeed signatures, on formal documents. One was found before all others, and is shown on this page:
You are not allowed to view links. Register or Login to view. under "Additional Signature". This one includes the "manu propria" scribble.

On 5 I would personally rank Wideman as quite possible, but Rauwolf and Mnisowsky (between Tepenec and Barschius) as unsupported by evidence.
Ownership after Kircher does not seem to be by any individual, and certainly Beckx should not be misunderstood as having been the owner at any time.

On 6, the link between the Marci and Barschius letters consist of several documents, including the Kircher letter in Moretus' notebook, Kinner's reference to Marci sending the book, and Marci's printed book referring to Barschius and his inheritance.