Application for flood insurance is dated prior to loan consummation, but then several letters from FEMA have trickled in with request for additional information/clarification "to complete the process of the insurance application". Is this considered a loan closing without insurance in place?

I assume you closed the loan based on the application in progress. If so, that stinks. If the loan has closed, there's not much you can do except inform the borrower they must get the requests settled and begin force placement procedures.

I agree, but isn't an application and a copy of the cancelled check all that is required?

Yes, but it is a risk as you have now discovered.

Yes ma'am, I agree.