Is there any character like that?

[oshfdk]

Try writing a few pages with quill on parchment and then look at your letterforms under a microscope (which is what this zoom level amounts to). Reading a handwritten text involves our brains constantly filtering out irregularities.

I think there is a caveat. If Voynichese is a ciphertext, we shouldn't exclude the possibility of the message encoded using tiny variations of strokes or letterforms (as in the Francis Bacon cipher, however, it postdates the MS by 200 years). For me the more important sign is not how small the variation is, but how unambiguously it splits letterforms into distinct groups. So, if it can be shown that for each ch it's clear whether it's tip over the bar, tip under the bar or tip joining the bar kind, then maybe it's worth investigating. On the other hand, if each time you have to guess which one of the variants it is, this is not a good sign.

I've collected a set of ch variants from You are not allowed to view links. Register or Login to view. and f16r, and there doesn't seem to be any consistency in how the left curve and the bar are connected. There are a few outliers and a lot of variation in between. So, I don't think there are three different characters.