I don't have an eviction attorney for Hudson County, but you should familiarize yourself with the "Truth in Renting" document (http://www.nj.gov/dca/divisions/codes/publications...) and NJ Community Affairs website (http://www.nj.gov/dca/divisions/codes/offices/land...).

Zoning is potentially an issue but building code is the bigger issue.  

Lots of places have an illegal basement and what makes them illegal is that they do not meet code for someone to live in them.

But of course, mortgage guidelines are not the tax code.

Wall and floors will likely not be level there are usually multiple additions from different decades and building codes, if any.

The code inspectors have files on the property but they're all marked closed.  

I would check with local city codes and make sure what licensing is required, you are essentially operating a hotel model.

I also try to "break" the product before it ships.I work closely with the developers to make sure the code they write does not negatively affect our product in anyway. 

They should be vented to the exterior otherwise they only serve the purpose of being a coarse particulate filter and do little for the air quality within the premises.In the IBC/IRC and building code in many, if not most, jurisdictions range hoods must be vented to the outdoors.

Best way is to obtain authorizations for release of credit, tax returns, assets and liabilities, then send copies or get several originals to use, mail them  and obtain information directly from the source, this cuts out the chance of fraudulent statements.You also need to underwrite the type of business, what hazards are present, toxics, fire, insurance coverage, competition with other tenants, traffic counts, environmental laws applicable to them as well as your infrastructure being sufficient for tha use.....electrical, plumbing, traps, fire codes, etc.