The most basic coverage they need is $1,000,000 of General Liability coverage per occurrence. 

Rental loans are based on DSCR, debt-service coverage ratio.

They are usually like $600-$800 for a good one for a year's coverage.

Best of luck Where can I find a comprehensive list/map of all areas that previously flooded?

Buy the umbrella coverage. 

I asked if we could knock down personal property coverage to a lower number but apparently I can only lower that if I lower the dwelling amount.Should I lower the dwelling amount?

First step is to discuss the project with the planning and zoning dept to find out if you can build and what the requirements are like setbacks, lot coverage, height restrictions, parking requirements, permits required, permit fees, impact fees, proffers, utilities costs, sidewalk curb and gutter requirements if any etc.

go on huduser and search for Comprehensive Housing Market Analysis. 

You have $1,000,000 in coverage with a $5,000 deductible.Repairs cost $4,995.

I asked if we could knock down personal property coverage to a lower number but apparently I can only lower that if I lower the dwelling amount.Should I lower the dwelling amount?