What is the credit requirements they look at?

Closed-end private equity style offerings generally have very different liquidity profile than a private credit fund (or interval funds), where the investor lock-up period is generally longer, with most of the returns being generated at exit (or back-ended).

I have great credit, killer salary, and a bunch saved up but still can't afford a 20% down payment on anything over 600k. 

If you have decent credit (north of 680), you should be able to get 75% loan to value, assuming the DSCR is met (usually a 1 to 1 measurement between the PITI and the Gross Monthly Rental Amount).

They also have accountant access to my bank accounts and credit cards, so everything gets reconciled.

But... you made so many mistakes:(1) No Personal Guarantee: try getting a loan of credit card for an LLC.

Growing up, my mother and I were renters, and I vividly recall the gratitude we felt when a landlord took a chance on us, despite my mother's imperfect credit history.

The people who are helping are genuinely nice people, but NOBODY should be clicking a random link left on an internet forum, that is just common sense.

Many attorneys charge a consultation fee that will be credited to my bill if I continue to work with them but I don’t want to pay for various consultation fees unless I know for sure that I have contacted the correct attorney.

I would expect the one in his personal name shows on his credit report as a mortgage and the lender will factor it in his DTI.