My question involves criminal law for the state of: NJ.

My age is over 18.
I was charged with shoplifting with misdemeanor (don't exactly remember the penal code..), got booked/fingerprinted/photographed for stealing about $15 worth of stuff.

I will not go into explaining or trying to "justify" because it was a long and complicated story, but however my lawyer was able to convince the prosecutor and the judge.

As a result, I got ACD (adjudicated conditional dismissal?) which the case got dismissed after 6 months, no fine/probation/whatsoever.
However, since I was booked, I had to expunge my record but now came the time I have to apply for graduate school and certain license.

Because it involves law, some people tell I still have to disclose the expunged record that I got arrested, and some people tell I do not need to because my case got dismissed and arrest record got expunged.

Do I need to disclose any of the information? Does FBI still have my record? (In other words, did I waste over $3000)
Also, I had to show up and talk with the police officer in the station for a few hours because of "fighting over phone conversation" but I was a minor, and neither the police did not charge anything. It is not in the record whatsoever, is this correct?