With respect to the crayfish, I see that Nick already recommended you to get into contact with Ulrike Spyra, a recommendation that I also just wanted to pass on to you. She writes quite a bit about the lobster/crayfish ("Krebs") in the various copies of Megenberg's Buch der Natur.
She picks up on the fact that there are one or two in which the lobster has six legs instead of eight, and that they are unnaturally red (Augsburg and Würzburg copies), but not on the incorrect placing of them.
See:
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It seems that the Frankfurt crayfish has the same problem, while the Voynich ones do not. (Depends on how one is supposed to count the legs).
There seems to be significant literature on the possible composition of Lauber's workshop, the number of different artists and the examples they may have used.
She picks up on the fact that there are one or two in which the lobster has six legs instead of eight, and that they are unnaturally red (Augsburg and Würzburg copies), but not on the incorrect placing of them.
See:
You are not allowed to view links. Register or Login to view.
It seems that the Frankfurt crayfish has the same problem, while the Voynich ones do not. (Depends on how one is supposed to count the legs).
There seems to be significant literature on the possible composition of Lauber's workshop, the number of different artists and the examples they may have used.