According to Article 33 of the Provisions on Protecting Lawyers' Practice Rights according to Law, in the case of major changes in the defendant's confession and refusal to defend, the defense lawyer may communicate with the defendant with the permission of the presiding judge. Therefore, item A is correct.
According to the second paragraph of Article 25 of the Provisions on Protecting Lawyers' Practice Rights according to Law, lawyers can apply to the people's court to bring paralegals to participate in the trial as needed. The paralegals can only engage in relevant auxiliary work when attending the trial, and may not express their opinions on defense or agency. Therefore, the mistake in item B lies in the second half of the sentence, and assistant lawyer Xiao Wang is not allowed to express his defense opinions when attending the trial.
According to Article 35 of the Provisions on Protecting Lawyers' Professional Rights according to Law, if a defense lawyer pleads not guilty, he can express his sentencing defense opinion in court or submit his sentencing defense opinion after court. Item c is correctly stated.
According to the second paragraph of Article 3 1 of the Provisions on Protecting Lawyers' Practicing Rights according to Law, during the court trial, the judge may guide lawyers to ask questions and debate, and the judge shall not interrupt or stop the lawyers' speeches according to the procedure at will, except that the speeches are too repetitive, the relevant issues have been agreed at the pre-trial meeting, are irrelevant to the case or insult, slander or threaten others, and deliberately disturb the court order. Therefore, there is an exception to the statement in item D, which is wrong.
Therefore, the correct answer to this question is AC.