Legal Question in Civil Litigation in California

I sincerely suggest that you get an attorney. You have the legal language all mixed up. In your initial question, you referred to RJN, as if it was supposed to be a term with which attorneys had familiarity. It is not. Now, you ask whether opposing argument will suffice. The answer is that opposing argument is all you can offer. The form of the opposing argument is very important. Then, you refer to having the judge "expunge the demurrer pleading." A demurrer is not expunged. You can oppose it. You can move to strike it. Expungement is not for demurrers. Also, a demurrer is not a pleading. It is a challenge to a pleading, and it may be based on the pleading itself, on verified discovery responses, and on matters for which the court may take judicial notice.

I know that the legal process can be confusing, and you appear confused. Get some legal help with an attorney.

You filed a complaint by yourself. They have an attorney. You don't. Case closed.

Mr. Saltzman is 100% correct. That you are so completely confused even about the terminology of what you are doing, clearly shows you are going to get run-over by a legal freight train in court, unless you get a lawyer.

Correctly handling a lawsuit , especially if it is an unlawful detainer, requires that you follow certain rules, whether or not you believe them to be necessary or correct. You seem to feel that following the rules is not really necessary. If you express that type of attitude before a Judge, they are more likely to rule against you, even if your position is legally correct. Judges are biased against parties who are in pro per, even if the party is an attorney.

Heed the advice the attorneys have given you and seek the help of an attorney before you are too late and loose the right to oppose the demurrer.

Demurrers are sustained or overruled, they are not expunged.