Hi Luke,
Thanks for letting me know. Since I don’t own a copy of Avada I can’t test the issue myself and I’m going to need a little help to run 3 simple tests:
1) My immediate suspicion is that Avada is removing other metaboxes on purpose. To test this you can download the plugin Simple CSS by Tom Usborne. It will add, just like FPS, a metabox to the pages screen. If after installation (and activation) the Simple CSS metabox doesn’t show, Avada is most likely removing metaboxes.
2) Another possibility is that you might have to enable FPS within the screen-options tab (in the top right corner of wp-admin when on the edit page).
3) Lastly, within: Settings > Fast Page Switch you are able to control what post types FPS should work for. Perhaps it’s disabled.
Please let me know about your findings. I will keep an eye out for your reply.
Thanks,
Marc