Will a marine with a njp get a dishonerable discharge?

One of the good things about Non Judicial Punishment is that it is not considered a Federal Crime. One or two NJPs will not typically result in a dishonorable discharge. If you are dismissed due to NJP violations, then it would be a DD. Depending on the NJPs and the types, it could reduce it from an Honorable Discharge to a General Discharge.