This is after covering all expenses and setting aside a certain amount for reserves to cover future expenses like capex or vacancy. 

If a person has RCV or ACV policy makes a huge difference, than question of what coverage level people had and if they had policy add-on's that cover cost over-runs and all that fun stuff, not to mention contents. 

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

Also note that my company will possibly either cover closing costs if we sell or provide property management for two years if we rent.

Anyone have a cheat sheet or checklist for covering your ADU bases?

You magically get the seller to cover every single closing cost (A $12k gift, or a trick to get you to buy their problem.).

I'd look at the closing docs for something related to the pro-ration of expenses etc and see if you have anything there that could be a clause you point to for them to cover those payments. 

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

I used a HELOC to cover the down payment, appraisal gap, and furniture, allowing me to enter the STR market without depleting cash reserves.

Those that own it can be harder to sell as the cash flow from the business will cover the debt service for the business, but not for the real estate.Example: I had a very high-end assisted living facility on the market.