@elliot
I built this function to use in my projects. I think it gets a little bit easier to edit without the distraction of many elements opened at the same time. The list is focused in order the elements and the edit button works with the content.
Download the plugin to test, the idea to create the modal is just using CSS, not moving the html content to the modal!
https://wordpress.org/plugins/acf-flexible-content-modal/
