(2) Periodical agency, but you are slow to contribute, and there is an intermediate channel that can help you contribute quickly, review quickly and publish quickly. There is nothing illegal in this, so it is not illegal. If it is a fake periodical, it is illegal.
(3) When choosing periodical agency, websites should pay attention to avoid publishing in fake periodicals. I suggest you go to Tao Tao Paper Network to see the knowledge of distinguishing the authenticity of periodicals.