VMs (f80v) critter identified

[Koen G]

It doesn't have to be just one reason.

I agree that we are probably dealing with a combination of factors. 
Some of the images are very badly drawn. They show a clear lack of skill. But then on the other hand, proportions of the nymphs are rather consistent, and a trademark of bad artists (like children) is variable proportions. Various plant  drawings are relatively complex and well executed. 

Of some images I feel almost certain that they are exact copies. The Zodiac figures are clear candidates. Others almost certainly must be new compositions for the VM or its now lost source. But even in those there are so often echoes of other works, like Balneis.

The problem Voynich researchers/ theorists so often face is that a leap of interpretation is usually required to bridge the gap between VM and proposed source image.