Did you go to the Tax Lien Code seminar that came here recently?

Establishing relationships with local real estate agents who specialize in investment properties can be incredibly beneficial.

Is it ok to use this lease or is there a special lease out there for leasing residential properties to a business?

Research or get referrals for RE brokers or wholesalers you specialize in off market deals and develop a relationship with them. 

I have sent postcards with QR codes for owners to scan for market updates.

We're a direct lender specializing in bridge, fix and flip, ground up construction and DSCR .

What @Jay Hinrichs is saying is that if you go before a judge, and you show that these leases were signed for significantly under market value and signed just a few days before closing, there is a good chance the judge will side with you because it is an obvious attempt to pay less rent and take advantage of the new owner.I think your next move should be to contact an attorney in your area who specializes in landlord tenant laws in NJ, and see what they recommend. 

I personally did a double major in accounting and finance and while I do not practice accounting as a CPA or bookkeeper or anything it has helped me tremendously to navigate real estate and understand the tax code or where to find answers to tax questions.  

But it becomes a much less attractive investment to an outsider when you know you could be facing future special assessments like that.  

I specialize in single and multi family investment properties.