I plan to invest in nj where house appreciates well. how to do I find the true appreciation rate for certain towns ?

Not exactly, too many variables.

Reason I do not want to do a cash out refi on my primary is because my rate is locked at 2.7%.

If you don't have a primary residence yet, I would highly recommend house hacking first.This is a great strategy to use low money down, get into an investment property, have a roof over your head and still keep a large portion of that inheritance. 

2 Years ago today, instead of renting a studio apartment, I bought this 3/2 single famliy house in Apopka, Florida, rented out the 3 rooms and converted the office into my bedroom.

I'm looking into potentially house hacking a small multi-family home, preferably in northern NJ (such as Morris county) or Westchester, NY if possible, but I'm open to other areas that are hopefully within about 1.5 hours (driving or public transit) of Manhattan.

The house at that time was probably priced around 1.3 million.

I just sold one of my OREO in Jackson MS.. 1 year ago as a vacant house needed full rehab I might have gotten 25k from a local for it.. just went into contract last week with a hedge fund for 71k NET to me they pay all costs and back tax's.. so something is in the water. 

Rates/pricing has to play a part of course, BUT knowledge and responsiveness is actually more important. and to answer your second question, well, look at my last sentence for the answer. 

There may be some dividends,  but not a ton and in the US have their own pretty favorable tax rate now.