You will miss the 3-yr window that you correctly identified, but you might still qualify for a reduced exclusion.

Seller(Lennar) already started selling for lower prices due to Coronavirus effect, can we ask them to reduce the price?

Might be good to start with one of those and give most of your time and energy to move the needle. 

Stop or reduce meals out (again, easier these days). 

Look into ways you can reduce your outgo.

Now that that is accomplished, we’d like to know what other seasoned hosts use as standard practice that isn’t too restrictive in nature and doesn’t inhibit  steady bookings... but reduces risk to the property.  

So instead they weld people into their homes to let them die (Communism vs Capitalism, I'm glad I don't live in China).https://techcrunch.com/2020/03/19/french-study-finds-anti-malarial-and-antibiotic-combo-could-reduce-covid-19-duration/

I offered asking on the property since it met the 1% rule and I could cover some missing or reduced rents no problem if we had issues with payments due to Corona Virus.

It's hard to tell what is happening to the overall money growth at the moment, but we know that private money growth has slowed (for obvious reasons) and public money growth has accelerated.Velocity of money could potentially be impacted the same way that it was in 07-09, when people responded to uncertainty and reduced incomes by pulling back on spending to pay down debt, build up balance sheets, etc.

The recent eviction ban further reduces protection for landlords.When getting a new tenant, would you negotiate for additional terms to protect yourselves financially?