As for the insurance aspect, it's always best to get the numbers from an independent third party.

When we put solar on our house, they were very clear that if we wanted grid independence, we would also need batteries.

Find an independent inspector that might has a history of construction experience (semi-retired) and they will be most candid with you vs just playing CYA for liability purposes.

You should run that report independently, and also search for legal actions (evictions & unlawful detainers), and any criminal convictions.As a former property manager to a few large apartment communities, I tell you that 90% of problems come from poor tenant screening.  

My lender requested an audit trail for every transaction greater than 1% of the purchase price of the property (e.g. all transactions with value greater than $840,000 * 0.01 = $8,400).

I've seen studies from independent third-parties that totally disagree with that statement (Northwestern, Stanford). 

I would recommend contacting multiple Independent agents and get quotes that way.  

What is the best way to draft the rental agreement, so they can be independently responsible for the unit and their rent?

My preference would be to find a reputable lender to do a cash-out 30-year loan based on the value calculated by an independent appraiser.

Best of luck Tyana.For more understand regarding the insurance I would google independent insurance agents around you to start.