"Ya'll" is not something I hear on a daily basis where I live. I rarely hear it at all. I sometimes say it jokingly, if I'm being silly, but "you guys" dominates by far. Even "ya's." "How ya's doin?"
Also, this is just me but I don't like the term "General American" or even "newscaster accent." There is no "general" "neutral" accent IMO. Certain people may think they have that accent, aka they think they have no accent, but to others' ears they do. One of my best friends is from Southern California and she says certain words very, very oddly to my ears. I instantly notice it. She has an accent to me. I have an accent to her. Everyone has an accent. Just because they haven't termed the "West" accent yet (and because the West has fewer and less interesting accents than the East) doesn't make it "general" or "neutral." Just my opinion. And anyway, who's to say what the "General American" accent is anyway? The East was populated and formed first, it's where this country began, why isn't what's considered "normal" an Eastern accent? Just a thought.
For the question, I don't know how many accents New Jersey has. The easy answer is two distinct ways of pronunciation in the north and south parts - respectively "wah-ter," "wood-er" for water and stuff like that. But it probably goes a little deeper and gets more complex than that. For example, while people from Hudson County have the North Jersey "caw-fee, dawg, cawl, tawk," (coffee dog call talk
) typically thought of NJ accent, I think at the same time the Hudson County accent is stronger and more distinct than other parts of NJ, even more New York (Staten Island/Brooklyn) like.