It definitely took some getting used to! By the time I finished I couldn't be bothered by getting the files and scripts all condensed in one .tscn so that it can be injected as a mod. And honestly,I'm not quite sure how to go about modifying the config file (especially since it needs a load() method called and a modification on an array that's been declared as a const. If you or anyone else wants to take a crack at it, you can download the files from a zip here: hotscreen_conditional_collection_files.zip. Just be sure to keep me updated on any further development and maybe throw some credit my way if it's integrated.
Edit - My code was a bit scuffed. I hadn't set it up to save anything. Fixed and reuploaded now to save the child collections, state of each selector element and the logic tree.