Details there don't matter, however what does matter is that we're about to bring home a sizable chunk of change in the next month.

Here is a link for the property itself: https://www.realtor.com/realestateandhomes-detail/309-N-4th-St_Decatur_IN_46733_M34729-76412#photo0Apologies for not having an analysis report to accompany this question.

They have not provided any detailed reports or receipts of any materials of labor.

If you don't want to disclose the source, that's fine; I'm actually specifically interested in knowing if your source provides you with details about the private note itself.

I know this is a gray area and not all agree on what constitutes an in-law :/ Thank you in advance for wading through all the details and any light you can shed. 

Cody ,Some day your going to have to sit down and write a book on how that is done in detail 

Once you have a foundational understanding, you can refine your knowledge through blogs or forums that address specific topics.You should also find a real estate investors group where you can network and learn from seasoned pros as well as newer investors.

My questions are 1) Is it better to get a "separate" address or should I ask for Unit A (main house) and Unit B (ADU)?

I stand by my statement, and based on the few details provided here, it's more than just likely this space would not be a fit for a national restaurant tenant (either as franchisee or corporate signed deal). $1 psf/mo NNN ($12 psf/yr) NNN speaks volumes about the location from a national restaurant chain perspective. 

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.