You just asked this same question in another thread and accepted an answer from Rob on this exact topic.
You have been given the answer. Your level data files do not have to have anything to do with Composer. They just define the level layout, graphics and so on. To learn how to structure them, read that external modules tutorial corona put out on their blog.
These “rules” you mention are not some magical thing that is different from anything anyone has done. They are just properties and functions that define behavior and can be put in an external module, hence why you should read the modules tutorial.
The only part where composer comes in, is to handle the screen flow of going from menu to game and so on.
Composer is supposed to be used for handling scenes, it doesn’t have or need any direct ties to your level data files.
Your level data files define what i said above, then in your game scene you build your level based on the properties defined by your level data module.
I know you will choose to not understand and ignore this advice, as it has been given to you countless times, but take it or leave it