Solid cash flow ($100+/door/mo) will protect you from many unexpected events and at this point anything is unexpected since no one has a clue what is going to happen in the next few years (or even the next few months). 

HOWEVER, I have a $20,000 reserve, strong W-2 income, no debt, the house is newly renovated and won't require much maintenance for the next 5-10 years, and other things in place to protect me. 

That would either be cash money out of your pocket, equity from your property (tapped through a HELOC, HELoan, or a refinance), or cash money from somewhere else (private equity, a personal loan, etc).So basically, it's either going to have to be paid by insurance or from cash/equity.Regarding the LLC - I've generally understood this to be a good move, more for legal protection than credit score optimization. 

Find a great agent (I have one).If you decide to partner on the deal, draw up a Joint Venture agreement, or a joint LLC with an operating agreement to make sure you both are protected, and what to do to exit the partnership. 

@Seth Larson can you imagine a scenario where the tenant refuses to pay anything, destroys the place, and essentially becomes a protected squatter?

Holding in a Qualified Trust Account or Qualified Escrow Account will protect you in case your QI files for bankruptcy and as you know, these are unprecedented times.

I do however have a couple follow-up questions:What protects you against the current owner taking the $600 monthly payment and pocketing the cash instead of paying down the mortgage?

Remediation is largely to protect you from liability. 

That protect the landlord for suits based on Libel, Slander, and the like.

Most new people don't know how to make an offer or what contingencies are needed in the offer to protect themselves.