Can you help me understand why an appraiser would have to give proof of their E&O insurance to a mortgage company for a DSCR loan?

If you still hold title, I'd get landlord insurance. 

Additional Insured is a no-no because the insurance carrier may refuse to pay an otherwise legitimate liability claim from the tenant to the landlord because insurance companies don't pay claims between parties that are insured by the same policy.

I'm curious - how many people out there are insuring with NFIP vs. private flood options?

Quote from @Anna Catron: Has anyone used the NREIG Affiliate BiggerPockets endorses for insurance? 

I have been working with insurance brokers to quote insurance for the property.

Insurance is an estimate until you get a quote, but a quick call to an agent with the address will give you a realistic number in minutes.

I am using STR insurance policies.

@Leigh FraynI have a few insurance broker contacts.

Being listed on the policy AT MOVE IN as Additional Interest (not Additional Insured, but that is another discussion) is key.