Hi RickiRu!
Unfortunately, no. The source folder is your original files and need to be there for the exe to serve them in the webview window. Wapper creates a custom webview wrapper for your files to be served to, that's what the exe is. It looks in the source folder for the files to open in the window.
As for the license folder, you should be able to remove the license folder, but you should leave it in there if you plan on distributing the app/game. The licenses are required to distribute the underlying libraries that make the output app work. Wapper automatically adds the needed license files to make it easier for you.
Thank you for the question and the kind words!