First of all, I think you have too many ideas. The reason you are having trouble making your paper flow is that you are trying to do too much. You need to choose one central idea, and then develop it through your arguments.
I am not sure what you are planning on for a thesis. You should devise your thesis statement first. It should be a brief, concise statement of what you plan to prove. It sounds like you are interested in how language is used in the paper. Are you arguing that the story is more persuasive because of the way language is used?
For example, your thesis might be:
In "A Modest Proposal," Swift uses language to ______________________ through clever use of ________, ______ and _________.
Finish that statement, and then choose from your ideas to support it. I strongly suggest you choose three. Choose three from your list of figurative language, tone, detail, the idea that it is fictional, syntax, and diction. Then support each one in a paragraph with specific quotations from the text.
Don’t worry. You’re on the right track! Once you streamline your essay a bit the ideas will flow more easily.