Those markets are higher priced and require a lot of capital. 

For example in and around DC some jurisdictions charge insane fees for new builds ($40k school impact fee) and have very challenging code requirements (sprinkler systems in homes..)Anything crazy like that?

Blanket Additional Insured - It is an endorsement that normally gives Additional Insured status if it is required in a written contract2. 

So if I can follow this model and achieve similar-ish returns with limited amounts of work, I require a greater return than that from real estate.

You can reinvest into sponsored investments or funds that don't require you to go out and personally borrow money at today's rates.As a 1031 accommodator, I'm clearly a fan of exchanging. 

I have two 3-family homes and 1 duplex, none of which trigger the commercial loan requirement.

You should put the property under an LLC Your third question is referring to the short term rental loophole, which requires 100 hours and more then anyone else of "material participation".

If that doesn't cover the principal balance plus all accrued interest, exit fees, yield maintenance, prepayment penalties, default interest, advances made for unpaid property taxes and insurance (even forced placed insurance), advances on senior loans, foreclosure costs/fees, toxic waste cleanup, costs of resale, the list goes on and on...the lender can sue each and every one of you for the entire unpaid amount.The way this would likely play out, should the lender elect to enforce the personal guarantee, is they would file suit naming each partner as a defendant. 

You could do that, but it is not required and the costs likely outweigh any benefits. 

Would be interested in the real estate side of things of course but I know there are other requirements connected with the medical side of it.