To answer the 1st question regarding no JSON binary being exported, the json file is exported to the Aseprite's file directory (meaning there is no control on where it goes). Perhaps I could add a setting for that if needed.
As for the 2nd question about the export being marked as "Successful" but no images actually being in the json file. I assume you were using the script with "GroupsAsSkins" set to false (turned off), I realized there was a problem in my script and corrected that, view v2.5.
For the 3rd question, that's actually a great idea. I will add an example project to the repository to better display how the script works / should be used.
Some additional information that I think should be mentioned. When I made the script I had the following project structure in mind:
Every asset folder would contain the contents displayed on the above image, for me this method is more simple having 1 folder for 1 asset. That being said, I am aware some people prefer organizing their project with the 1 folder per type method (meaning all spines in 1 folder, all aseprite files in another folder, etc.).
If you organize your project using the 2nd method, I do not think my script would accommodate you at this time, however I could add support for the 2nd method if need-be.