It depends on the forum you are in. There might be subtle differences between, for example, Civil Court and an administrative agency. But generally, the differences between the statements are consistent with their titles. Typically, a pre-hearing statement is a brief summary of the issues that need to be addressed. It's kind of like opening statements at trial, but in a written form. Usually, a hearing statement is a bit more detailed and includes some discussion of the evidence that is being produced to support the assertions made in the pre-hearing statement.
It appears from the categories you selected that you are in court, not an administrative agency. If so (and assuming you do not have legal counsel), there are often "pro se" or unrepresented party departments in the various courts. These departments help people like you navigate the court processes. Of course, if you have an attorney, he or she should answer your questions. You might also consider at least consulting an attorney so you do not miss important deadlines or fail to make key arguments in ways the Judge will fully understand. I am particularly concerned for you because you seem to be confused about the forum you are in, and I want you to make sure you get your most effective day in court.
My response is for general information only. It is not legal advice, and it does not create an attorney-client relationship. There is rarely a black-and-white rule or a "one size fits all" answer to a legal question. Please contact an attorney for specific legal advice regarding your matter so you can customize a solution to your needs and desires. :)
You should consult with an attorney in your area specializing in this type of matter; it is important to disclose all the facts and to explore your options. Be prepared to pay a consultation fee and know what it will be in advance.
It is time for a lawyer, not a website, to discuss what claims you may have. AVVO is a free general legal information blog, not a substitute for legal advice. Look for an attorney you would like to have a consultation with. You can use Find a Lawyer tab above, right here in AVVO. Select an attorney, contact them directly and schedule a consultation. You might be glad you did.