They might prefer to see the funds used for improvements on the property securing the HELOC.

We also have preferred venders in place for lending, insurance and Property Management.  

I much prefer Loreto or Mulege. 

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.

This is why I prefer to have Property Managers for properties who know all the landlord-tenant laws in my rental cities.

The one issue I think I’ll have on my hands is I prefer to house hack again in the same town (appreciation seems to be great along with rental amounts) but I’ll need to refinance my current house hack into a conventional which I doubt is at 20% equity yet since I don’t think I’ll have a valid excuse to have two owner occupied loans in the same town.

@Charlie Brown, I'm not super familiar with your market specifically but I think this strategy works anywhere:- Find a boutique, niche, ideally aging broker/brokerage in your market, and start adding value. 

Logically, if you fall into any of these fields, get a property manager:Located far from your rentalAren't familiar with the laws in your stateDon't have a way to properly fill work ordersI prefer going with PM's because they alleviate the stress of dealing with the property itself, so that I have more time to focus on other things (like getting more properties!)

I know it is a niche area of REI, and figured that there would be no better place than BP to meet and learn from any investors who have had success in this area.

Most folks would prefer to drunk drive home from the games unfortunately.