In my opinion, it might be good to post a query similar to this in r/Newark, if you haven't already, and to stay at an AirBnB in the Jersey City Heights, if possible.

My feeling is that downtown Jersey City was the cool part of Jersey City a few years ago, but that the Jersey City Heights and the area around the Journal Square PATH station are now younger and more interesting, because the rents there are lower.

One example: The farmers market in the Heights is simply much better than the farmers markets downtown.

Downtown Jersey City has nice coffee places, but Cafe Peanut, near Journal Square, has enough room to have live music on Sundays.

Along the same lines: It just seems as if the most fun parts of Newark must be a lot more interesting than Jersey City, because Newark has three real universities and is so much cheaper than Jersey City.