I agree that when someone ties up a property where the deal doesn't have a chance, that they're doing a disservice to the seller and to themselves in the long run.

I'd just reassure them that if someone is ill, to remain in their unit. 

And your Father who sees in secret will repay you.Matthew 25:35-36For I was hungry and you gave me food, I was thirsty and you gave me drink, a stranger and you welcomed me, naked and you clothed me, ill and you cared for me, in prison and you visited me.Galatians 2:10Only, we were to be mindful of the poor,* which is the very thing I was eager to do.1 Timothy 6:18Tell them to do good, to be rich in good works, to be generous, ready to share1 John 3:17-18If someone who has worldly means sees a brother in need and refuses him compassion, how can the love of God remain in him?

You need this itemized list anyways to send back with their security deposit, or lack there of.The list and any remaining security deposit, or a bill with payment instructions gets sent to them via certified mail, so you have a record of them signing for it. 

The amount of time a tenant can remain as squatters is unknown.

In prep for that: I have about 50% equity in my home (value 2Mil+) - and I have the following cash-out refi options for the remaining mortgage amount - locked.

Your major systems that were replaced at the beginning should still have at least 50% of their useful life remaining. 

Useful life remaining is max 10 yearsQ: when i depreciate the building, will it be for only 10 years (remaining life)...so lets say salvage value is 50K. so I will depreciate 30% of cost = 330K minus 50 K salvage = 280 over a useful life period of 10 years = 28K per year?

Real estate values are not tied to the stock market, and the fed keeps lowering interest rates which I think allows the real estate party to continue.

Their problem is not COVID-19, but the firestorm of price requests from wholesalers hoping to tie up a property on a 20-day price quote, and then attempt to find a buyer.