If you don't subpoena the officer then they go ahead with out the officer and base the decision on the paperwork submitted. You shouldn't be handling this without an attorney since this is your license at stake, and you only get one chance. You may or may not want the officer there. You may or may not want the video. You may have defects in the paperwork. A trained attorney can help you with this hearing and I don't suggest you proceed without hiring an attorney.
Yes you can have the video subpoenaed along with the officer. However, it may not always be the best idea. You really need to have an attorney review the evidence to see if issuing a subpoena is a good idea or not.
Almost all criminal cases involve someone else's say-so. It's how the system works, but as you can guess, it doesn't always work the way it's supposed to. That's where an attorney comes in. If he is NJ, then you need to contact an attorney there to help your son. If the charge is from Florida, but he is being held in NJ pending extradition, then you need to contact an attorney locally.
Hearings rarely take place in the judge's chambers, and in criminal cases, practically never. An attorney may talk with a judge in chambers, but it is not a hearing. Since you are nervous, it will be well worth hiring an attorney. You may get much more than 15 minutes and in fact with an attorney, you will be able to get all the time you need.
Attorneys usually do not show up for arraignment as a written plea is usually entered. Nothing to worry about, but you should talk to your attorney to make sure you're informed of the progress of your case.
First thing is to let your attorney know. They are obligated to straighten this out for you if that was all parties' understanding. It's possible that a motion can be filed to fix this but talk to your attorney about your options.
It would be near impossible to tell you what is going to happen. There are way too many variables. Further, the charges could be anything from a misdemeanor, for small delivery of cannabis, all the way to trafficking in marijuana, where there are various mandatory minimum, starting with a 3-year all the way up to a 25 year mandatory minimum depending on the amounts. Needless to say, he needs representation immediately. Finally, do not discuss this case on this or any other forum as...
It is possible for it to be attempted manslaughter. Also, the others involved could also be charged and would probably be equally culpable. However, it is more likely that they would charge aggravated battery. That charge and attempted manslaughter are both second degree felonies and face up to 15 year prison. Even a person without any prior record "scores around 5-7 years prison, so this person accused of doing this needs an attorney immediately.