It's really hard to predict where regulation will go and it is indeed one of the risk factors for all investments.

Another option would be working with private lenders to see if they're open to your idea should you need additional funding. 

I can give some additional feedback in the coming weeks. 

If your goal is passive income, it's not going to be in New Jersey when you factor in cost to purchase, management costs, and rent to price ratio, but what you can get is steady appreciation.

Both properties have a substantial amount of equity that’s essentially sitting idle.Would it be a good idea to tap into this equity (through a HELOC, cash-out refinance, etc.) to fund future fix-and-flip projects or purchase additional rental properties?

Of course the goal should be on the first page by anytime but that is usually bad ROI since the price is the biggest factor on the rank.

In addition to that, platforms like HomeAdvisor or Angi are great for finding vetted professionals, and local builders associations or the Greater Beaumont Chamber of Commerce may have directories or recommendations. 

Beyond that, networking with other investors in the mobile home park space could open up some doors for partnerships or additional funding ideas.

Quote from @Don Miller: The following is not to express any level of happiness or unhappiness with the build:Received change orders totaling $14,970 for 18 additional loads of fill dirt over allotted amount in contract (fill dirt arrived in December 2022), 7 loads of septic sand over allotted amount, and rock excavation at the septic site.I deal with all of those issues on new builds.

When its included in a lease for real estate then the laws pertaining to residential rental security deposits in your state apply but when its separate you should have more leeway to get some additional deposit to protect you.