It's bad enough when they go into an unbalanced spin cycle here on Earth, but it does seem that could seriously affect the stability of a space station's orbit. I was surprised this wasn't mentioned even in passing in the article.

That's not how orbits work. Shaking something inside the station won't change its orbit a bit. It's because to change orbit you need to change the speed you are going with. And that's just not something you can do by vibrating a mass.

That doesn't mean that vibrations are all safe. They can break stuff on-board, or mess up experiments. If you do it exactly right (wrong?) it can even change the attitude of the station. (after all the reaction wheels and Control moment gyroscopes look kind of like washing machine's drum if you squint enough.)

Ah, thanks for the information. Interesting that such vibrations can only affect the attitude and not the orbit itself. Keen to hear from anyone who cares to share more of the science involved here!

Maybe you don't need to spin at all because reducing air pressure would allow evaporating all the water at low enough temperatures?

Unfortunately the pressure has nothing to do with the energy cost of evaporating water.