If the investors aren't thrilled with their PMs, reach out to new ones through internet search and ask for references.

I am a licensed contractor and I have references.

When you say investment growth, are you referring to appreciation? 

Ie: are you referring to using hard money and cash?

In the way I'm discussing commercial loans for a SFR it is synonymous, but I think some people refer to a master loan made for a portfolio of properties as Portfolio Lending, so there's bound to be multiple meanings floating around.I find loans to an LLC to be easier than to a person, but I bet that is because I have some incredible vendors that I have built trust with AND I am not a W-2 employee. 

Are you referring more to owning an airbnb type property? 

I would tell him as long as he leaves the property clean so it can be rented .you will not persue him in court and you will still give him a reference.

Ideally, you would work with your tax advisor to determine (1) if you are a real estate professional and (2) if you materially participate in the rental real estate activity which you referred to in your OP.

@chad cosigner would come from your network if that's what you refer to.

Maybe a way to find out how to check the TIN credit is to ask for references, banking account information, current and previous landlords.