Your question pertains to amending the pleadings to conform to the proof at trial. This means that if your complaint alleged a cause of action which you prove at trial, but the same proven facts can also support another cause of action, the court is supposed to allow you to amend to add that other cause of action, even at trial. It does not mean that you can amend the complaint for new causes of action relying on facts that you did not fully present at trial. If you go to your local law library, they should have examples of this if you ask the librarian for books with examples on California Civil Practice and Procedure.
Your issues regarding defamation and SLAPP are very different. Perhaps the posting was just too chock full of different issues to fully answer, and you may want to break it down or consult with a lawyer on your case, so that you can rely on the information. With the set of facts that you provided and procedural issues, I don't think any reply to your questions can be reliable, since we have not reviewed the documents and entire procedural history to give an actual "answer."
There is no form other then a form motion. Many times the Court will allow a verbal request to conform to the proof at trial. Normally this motion is brought to conform proof on damages and possible claims for monetary awards so the Judge or Jury can award the amount that is supported by the evidence that is admitted at trial.