The rental market is also super strong, so finding tenants isn't too hard now. 

I would strongly encourage stronger screening procedures .

A 5.7% cap for a class B or C facility is a strong ask in the market. 

Expensive, high property taxes, cumbersome govt oversight, and a strong bias against landlords. 

House hacking would never be an option, her privacy is too important

I would consider speaking with a good insurance provider for a strong policy in addition to an umbrella policy.

investors that just got in the game post 2009  were spoiled in thinking that everything had to cash flow with minimum down and cash flow positive a lot.. when in reality in a strong market with good demand safe secure properties  minimum down break even is a great out come and many times a little bit negative while you wait for rents to inch up. .you make your money in appreciation and tax write offs and your tenant paying your mortgage for you.. 

I invest in Nashville myself and do have a lot of clients investing here still because even though the cashflow isn't that strong, the projected (and current) job growth and property appreciation is a draw for those looking to sit on a property and let it appreciate.

If you want to splurge and add a patio cover, that’s a nice touch, but it’s not cheap.Privacy: Make sure to create separation and privacy between the main home and ADU by constructing solid fencing in the appropriate location.

I post a lot on industrial, but for beginners I recommend anything that has strong tenants and high occupancy.