But if we purchase as individuals, how do we keep accounting separate from our personal finances?

Also, having a property manager may help to create some walls between you and the tenant who are already only separated from you by a wall.

Once you buy a property in the LLC make sure you separate your personal endeavors from your business.goodluck 

It’s no good to go in with emotions high! 

Having a separate bath was viewed as a convenience, particularly for the help. 

If that price point does not get you into multifamily, I'd recommend finding a single-family home that you can convert to a duplex with separate entrances or try a rent by the room strategy.

Whatever you do, maintain separate bank accounts for the business and set aside reserves for repairs and updates.

The phrase 3rd party is attempting to denote a separation between the website and a lender is it not?    

I am newly separated from my partner and starting out in real estate investing as a single mom with low 1099 income and few assets.

Mainly fire barriers, and extra insulation in between the floors. you could go with permits for the work that is being done if you want to avoid any concerns, but as far as the city will be concerned your home is just a single family that has a Mother-in-Law suite, and you are renting the spaces separately.