You should hire a lawyer to represent you, and work out the case for the best possible solution. There are punishments which can be cleared from your record later, or can minimize the negative mark on your record. Each of you will need a different lawyer unless you all waive the potential conflict of interest.
At any arraignment, you should plead "not guilty" or stand mute. At the pretrial conference, the prosecutor may offer a plea to be taken under advisement. While the conviction will appear for a time on your record, it should be dismissed after you've completed the terms of probation. In any event, the facts you related present several troubling aspects about the stop. You should consult an attorney before proceeding.