Saves me from having to transfer any amounts that add up into a separate interest earning account. 

You can either clearly list the 6% state sales tax and the 6% county tax separately in your rental agreement or invoice.

You probably want to keep the management company separate from the rental properties.

I think it's important to start with this - is your 250k debt what you owe in principal on the mortgage on your home or is this separate debt (credit cards, cars, medical, student, etc)?

If it's an apartment building, individual units can't be sold separately.

Is it best to find a property that is already divided or has a separate unit?

Taking massive action, networking, finding where you can add value and then executing is what separates the true entrepreneurs from wantapreneurs. 

How separated are the primary from the ADU? 

We as investors have to think differently from a newly wed first time home buyer that can overpay based on emotions. 

I'm toying with an idea for a system that would handle guest communication workflows using AI, analyze the feedback, and also trigger surveys post-stay/review for tracking performance.As far as I can tell, there's nothing out there that does those 3, but perhaps there are separate services that provide some or more of those.