So, the actual seller is probably not the issue here.

If you're interested in real estate, would you be able to make a pivot over to something like RE Law?

Best part is NJ is not what its made out to be in terms of landlord friendly, the state gets portrayed as the entire state being bad when really most wacky laws are in the major cities and they apply to 5 units or more.  2-4 unit multi families fly below radar per say. 

- what if someone is occupying the living areas more than someone else and it causes an issue? 

If you really want one then I would have one drafted by an attorney to make sure you are square on all issues, liabilities, scheduling etc.  

You will want to know your state laws regarding deficiency judgments, and whether your deficiency will survive the DIL. 

@Craig Oram this is a common issue.

@Shayan Sameer Yes in case the projects do not work as expected you will have an issue with paying off the HELOC  on  your properties unless you do a cash out refinance and then the risk is not so much as there is no second lien(HELOC)

I am having issues with one property I own in Cahokia.  

CA has it's upsides and both states have insurance issues.