For an extra step of protection, we do have an insurance policy on each lockbox just in case, however, we have never had to use it.I hope this helps! 

I'm not sure of how much I should be asking for as a return or if I should be asking for a percentage of the profits (as it may be substantial) and how/if I can protect myself of any possible negative outcomes.Thank you for taking the time to read this and many thanks for any replies.

With Private Money, you need to have your primary focus on protecting them and their investment.

The Garn St Germain Act would protect you against a due on sale clause.

Need advise on how to set up best and practical asset protection.

When in doubt I'd advise to extend a closing and pay a professional in their respective field to make sure you are protected. 

Hi @Parney Willson, my short answer is that there is easier and less risky money to be made in real estate than buying a condo with a rent stabilized tenant, in NYC.1) Condo - lots of additional due diligence needed on the condo association and risk to you if others do not keep up with their dues2) Rent Stabilized tenant - NYC recently implemented a new set of regulations called the Statewide Security and Tenant Protection Act 2019.

With industrial or properties involving hazardous materials (gas stations, medical offices) is the risk of environmental contamination usually covered by insurance (which the tenant would be paying for)?  

For example, if there is only 20 to 25% equity in the properties (that is a protection), there's nothing much for anyone to get in a lawsuit.

You'll save way more money by buying a place that doesnt gave environmental issues.