You have the right to face the accusers that the State calls to present evidence. The witness who gives information to obtain a search warrant does not necessarily have to be called at a Preliminary hearing or trial. At that point, the State can call the officer who testifies that pursuant to a search warrant they found drugs.
That said, whether or not the warrant was valid or not is a question for a pre-trial motion in which the defense attorney can seek to have the warrant deemed invalid, and then everything obtaine with it suppressed.
But your attorney also has the right to call witnesses at trial and cross examine the officers to try to bring these facts to light.
As for the possession with intent, the amount of drugs is not the only way to show intent. You should have your attorney look at the State's evidence and explain to you what is the grounds for the intent to distribute. It's a valid question.
This information is for general information purposes only and does not create an attorney-client relationship.
The right to confront your accusers is a trial right. At your trial, the informant will not be an accuser, therefore, you will have no right to confront him. If you make a motion before trial to suppress the evidence as the fruit of an illegal search, you might get the right to question the witness at the hearing on the motion. In some cases, you can call the informant as a witness at trial, and get a court order directing the prosecutor to serve the subpoena on the witness.
Of great importance is that you should not go around confessing on the internet. If this statement gets traced back to you, "I only possessed 2 ounces of marijuana," this statement by you could end up playing a major role at your trial, and could help sway the jury towards a conviction.