There's nothing in the law that requires you to send someone on a Sunday evening at her convenience.

Some lenders may also want to see law and ordinance coverage in your insurance and perhaps a rebuild letter from the city stating that the property could be rebuilt as a residential 4plex if destroyed. 

Check local law, whether you have to accept varies by state.

Make sure to understand disclosure laws in your state.

They just passed pro ADU laws here.

What's common practice?

Their practices are neither transparent nor honest, and I would not recommend their services to anyone.I have money owed to me and they have not sent an ACH even though they have my routing information.

Also, I'd lease out the other bedrooms for additional income as well as practice screening, leasing, and interpersonal comms.  

Real estate laws are local to the state where the property is located.

Currency pegged $2BZD to $1USD (low inflation issues), Official language is English since it was a British Commonwealth, Property rights and laws are basically the same as the US since English based, 2nd/3rd world thus still Rough which I like (has flavor), 2 hour flight from Houston/Dallas connections, land is relatively inexpensive.