So, here's some news.
I think it's news, anyway.
I was screwing around, trying to get the basic Prussian musketeer to use a Bicorne. I typed in the Bicorne path (the Prussia atlas file says it has it, so...) in the first 2 hat entries in the variant model file (there are 4 hat entries for the Prussian musketeer. Not sure what that's about). After importing the unit into my pack file, this is what showed up in the game:
As you can see, those are the Prussian Musketeers from E:TW.
Somehow, I made a mistake (obviously). The interesting part is that then the game defaulted to E:TW textures rather than the N:TW ones.
No, I don't even have E:TW installed. This is all within N:TW. And no, it's not a joke.
And also no, I haven't the foggiest idea what I did or what caused it to occur. What I do know is that Hex Workshop crashed while I was saving this file. But then I re-opened it, and it seemed to have saved fine. So I imported it into the game. This is the result.