Without a doubt a trait of a good Voynich researcher. I see no problem assigning percentages of likelihood to something though, so I think you solved it well.
Last chance to participate!
I'd like to change my answer to Q13 to "yes" because I hope that we have really hit the target with the plants mnemonics. That would be a breakthrough of course, albeit it might give nothing in terms of text at first.
Okay changed

- Does the text contain any meaning? Yes
- Has the text been purposefully enciphered to conceal its meaning? No (At most, it could be a code.)
- Do the images match the text? Yes
- Are the plants meant to refer to real plants? Yes (At least, the author considered them to be real.)
- Is the majority of the plants exotic from a European perspective (Asian, African, American...)? I don't know
- Have the images been made ambiguous or otherwise strange to conceal their true meaning? No (No more than was usual.)
- Is alchemy an important part of the manuscript? I don't know
- Is astronomy and/or astrology an important part of the MS? Yes
- Is medicine an important part of the MS? Yes (At least what was understood as medicine at the time.)
- Is the MS the creative product of one mind, i.e. an author? (Taking into account the possibility that one or more scribes helped to fashion the physical manuscript) Yes
- Is the MS authored by a known historical figure? No (They may be known in historical records, but not otherwise.)
- Will we ever be able to read the MS? Yes
- Will there be any breakthrough in Voynich studies in 2017? I don't know
- Is the MS any kind of hoax? No
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Open questions:
- In a few words, what is quire 13 about? (bathing, anatomy, angels......) Bathing, maybe with a focus on women's reproductive health.
- In a few words, what is quire 20 about? I can give no guess better than 'recipes', as there are no clues to its meaning. This is the reason I study the quire the most.
- If we were able to read the script, which language(s) would we read, if any? I still regard Turkic as the best option, historically and linguistically, but it could also be a systematically altered Indo-European language, or even a code-like language (but not a cipher, which is an important distinction for question 2).