You cannot examine the flat 21% in a vacuum. 

Paying two mortgages at the same time if school closes for a prolong time is a little bit nerve wrecking to me when I think about that.. but yes, I already included vacancy in my numbers, it is just not that much of vacancy (3,4 months or longer).

The funding part is probably the most confusing and nerve-racking part for me (and probably for most beginners). 

Never watched ot when it came out in 2011, so it was a total shock to me to see how predictable every phase of what's happened so far is, even in a pandemic with a disease with a far lower death rate than the one the movie examines.

As a self-defense measure, we are examining our resident’s employment, looking to see how many of our residents work in the hospitality, entertainment, restaurant and airline industries so that we are aware of our exposure to future rent defaults by residents employed in industries most likely to see job/hour cuts.  

Hard to say, but I would definitely compare last year return to this one and examine the difference.

Their perception of low- and high-risk markets is oftentimes exactly the opposite of what a careful examination of the facts would indicate.

Additional followup: Who all is examining refinancing eligible assets?

The degree of upside and delta is entirely up to you but examine in detail the things I mentioned above for a start.

SETTLEMENT COSTS: Buyer agrees to pay all settlement costs and charges including, but not limited to, all Lender's fees in connection herewith, including title examination and title insurance fees, loan insurance premiums, all document preparation and recording fees, notary fees, survey fees where required, and all recording charges, except those incident to clearing existing encumbrances or title defects, except if Buyer is a Veteran obtaining VA financing, those prohibited to be paid by a Veteran obtaining VA financing,which prohibited charges shall be paid by Seller.