Since then I've had a few other contractors come out and verify the work is not sufficient let alone up to code.

Do not hand over keys until you personally verify everything is done.

Verifying last 2 years of rental history very important!

In my area the water company will forgive excess usage if it can verify there was a temporary water leak causing it. 

The drawings can go back and forth but the rater needs to be local to the property because in the end he will have to go verify what came out of the build and prepare a reconciliation showing the actual performance numbers post construction. 

Today, they told him they have to verify funds and that they're "doing him a favor" by doing so.

Verifying last 2 years of rental history very important!

Have you verified these info?

Zoning and Land Use: Check with local zoning authorities to verify the property's zoning classification and ensure it aligns with your intended use.

There are great agents that will give honest advice on the deal but at the end of the day they want to get paid.Trust but always verify.