Did the scribes copy the letters correctly?

[oshfdk]

Just an experiment: what would happen if a person who only knows Latin would try to copy a text in Greek or, even worse, Arabic without understanding it at all, especially if it is not a very clear writing?

Nothing bad would happen most likely. I've seen kids attempt copying unknown scripts for the first time while traveling (Hangul, Chinese, Greek that you mentioned), the proportions would normally be wrong and the letters look weird, but still perfectly readable and recognizable, just with a few minor mistakes. Voynichese looks like a specifically designed script that uses various combinations of simple strokes in almost all possible ways, so I think your hypothesis is not very likely.

One exception would be attempting to copy something like the Chinese below, this would be nearly impossible, but Voynichese certainly doesn't look like that.