I guess a temporary rent adjustment could be done,but most likely the landlord will not get any break in his principal and interest payment or insurance or property taxes.
Doing this would be in the landlords best interest generally so hopefully when things return to somewhat normal the landlord won't lose too many tenants.
As far as crowded restaurants, I can't picture business ever getting back to normal,I wouldn't go.
Our community bank has given us three months of interest only. We own no real estate but he said the are differing principal and interest for three months for their commercial properties that are performing well. Every landlord has different financing but some are certainly getting modifications from their lenders.