Yes you can use Microthemer to style Zion Builder content. The workflow is to load the published page in Microthemer. Microthemer doesn’t care how your WordPress content was generated. It just needs to be created with WordPress. That’s what makes it a really flexible styling tool.
I have actually tested Zion recently, but if you notice any random technical issues with another WordPress product, please bring it to our attention and we will work on a fix ASAP. We’re committed to ensuring you can use Microthemer with any WordPress setup.
I hope that helps. Please let me know if you have any other questions.