She declares bankruptcy/pays off those cards with the cashed from the sale and moves forward investing as a business entity.additionally, her personal residence is income producing as well since she rents out two rooms on Airbnb and runs her cleaning business out of an office there. my questions are1.

It's tight and if you didnt execute your business plan, your staring a cash-in refi or sale square in the face. 

Business Lines of Credit are a different thing than a HELOC.

Curiously, if an investor has LLCs with business credit such as credit cards, LOCs, etc. when the lender pulls the borrower's credit do they also pull the LLC debts to calculate personal "net-worth" or do they just use FICO data, etc?

When you start with the end in mind, you have the advantage to look for a repeatable business model as opposed to what most noobs do: looking for unicorn as their first deal.

I am interested in learning a high level view of what these look like from an org structure standpoint, as I understand the gist of the business strategy in general.

I just got Chase Business Ink. if you spend $6000 you get $900 cash back (not sure how long this offer is) and 1.5% cash rewards on purchases. 0% APR for 12 months if balance is paid off by then. 

Some years back I sold a business.

We suggested they start a business and buy through the business name but aren't sure about that either. 

I've had a great interest in real estate since my high school days in NYC, and it all started with the love that I have for reading different types of business books.