it is technically a real thing but very rare, and there is plenty of historical data out there that shows those who have less skin in the game are at a far greater risk of default by a factor of 5-7x.

I think my main point, which you’re experience lends support to, is that while there are below market deals out there, it requires a continual effort of being “in the market” and looking at 100s of deals to negotiate the rare below market purchase.  

In Nancy’s opinion, this care model, combined with the social capital of a cohousing community when properly supported with trained staff can result in quality care.

Due to past poor management of the environmental infrastructure, the river has become illegal to swim in in certain parts, and after rain falls the entire river is off limits to swim or fish in due to the heavy amounts of pollution ending up there that the city has not had the infrastructure to deal with in the past.But this all began to change in 2017, when the Virginia General Assembly passed the largest infrastructure project in Alexandria's history to make the Potomac River swimmable, and fishable by the year 2040, and they have made significant progress recently with the completion of the 2 mile long, 100-foot deep Waterfront Tunnel named Hazel.Named after environmental activist Hazel Johnson, the Hazel Waterfront Tunnel will prevent millions of gallons of combined sewage from polluting the region's waterways.

Rare that happens. 

For example, I mention that every adult must pay a $30 application fee, pass my credit/criminal background, make a combined income of 3x the rent, and whether or not the property accepts pets.

Quote from @Mike Sfera: for a duplex, is the BP rent estimate for per unit of combined?

I hope you are asking two separate unrelated questions, because there's no point in doing cost segregation for properties held inside your self-directed solo 401k, save for some very rare exceptions.Some of the Bigger Pockets experts who operate reputable costs segregation companies are @Bernard Reisz, @Yonah Weiss and @Julio GonzalezSome of the Bigger Pockets experts who offer Solo 401k administrator services are @Dmitriy Fomichenko, again @Bernard Reisz and @Brian EastmanReach out to them and see if they can help.

Advice on Layout/Design: For those who have added ADUs, do you recommend standalone units, garage conversions, or a combination of both?

Quote from @Collin Hays:Merchants rarely win chargeback disputes.