This implies residential units can be built at lower costs and provide better return. 11) adding an ADU to SFH can make the SFH fall under rent control.

If they are marketing with some stated or implied financial outcome then I think they are more often than not a scam.  

It is just a different source of the  funds.  100% LTV implies no money from any other source. 

This is kind of implied in the other points, but talk to an attorney and know what legal exposure you might be looking at.

Buy the buyer qualified for the loan with the poor cash flow implying they can handle the poor cash flow. 

Sounds like there might be some more facts of the entity structures since you imply a k-1 will be involved but only reference ownership of property A.

Two studies have shown rent to value ratios have never been worse implying cash flow on the average purchase is at an all time worse.  

Quote from @Bob Regent: OK, I do want to be very clear that I am in no way implying that these investments were a scam.

You are an INVESTOR which implies risk.The only questions:1) How risky have your decisions been?

Its really important for people entering into any home improvement contract to understand the state laws for so many reasons, business and professions codes/laws, warranties whether expressed or implied etcThe point being is well executed legal contracts are best for all parties involved.