Is it a safe walk on a Saturday evening from NJPAC to here (Dom Pepe) for dinner?

Yes. There are always plenty of cops around. Just stay on the main roads. No small side blocks

Yes, we have done it before, even with our kids. They allowed us to leave the car in the parking lot until after our event. Just make sure you ask permission from the owner so they don't lock up the parking lot if you will be late.