Wow looks almost too good to be true. 

With that said is this a true underground basement?

True, @Caleb Heimsoth.

The exact example, could I set up an LLC, get a credit card in the name of the LLC, and purchase the BiggerPockets Pro Membership with that card and write it off as a business expense?

@Mathew Zorn if by revolving debt you mean you are carrying a balance on your credit card you should not be investing at all. 

I have constructed both ADUs and true Duplexes.

that was a rocket ship.. 180 knots true..but pull the power and it drops like a stone  .Me Cirrus Sr 22.. but semi retired from flying these days but flew that thing all over the US> 

They are good at covering small claims, but if a true negligent or 'fraudulent' accident happened, they will challenge the claim and then yo will be stuck defending yourself in a lawsuit while at the same time sing your insurance provider.

Per the City, the renter is not responsible for most costs and all of the financial responsibility due to a inhabitable area, is the landlords responsibility.All of these costs have been put on credit cards and have added up to nearly $68k.

They should have credit cards on file and have very easy ways to catch them.