Alternatively, an S corporation would treat those expenses as start-up expenditures under IRC Sec. 195.

Using those numbers, with 10% each for vacancy, capital expenditures, and repairs, I'm coming in at just over $100/mo for my cash flow, which is my goal. 

You also should set aside money each month for repairs and capital expenditures.

As a rule I generally assume expenses to be 50% of the gross income for my first look evaluation no matter what expenses the seller reports (unless its more than 50%, then I will use their number.)From there you can get into more detail on what type of capital expenditure budget the property might need depending on what physical condition and what strategy might be best.As far as due diligence once the property is under contract, or maybe before in some situations you will need a much more exhaustive list.

Generally you do not want to make any significant expenditure until the deed to the property has arrived.  

What you're alluding to are capital expenditures, or CAPEX, which can be depreciated as an expense over a period of time from the owner's tax obligation.  

This is not exactly an answer to your question, but might be useful information for you to have if you are forced to make improvements to the building to comply with ADA requirements.There is a tax credit worth up to $5,000 for making "eligible access expenditures" to comply with ADA. 

The 25% exemption noted above is designed for relief from market appreciation not capital expenditures.

So none (or little) of your 2016 expenditures would have been deductible on your 2016 taxes. 

My recommendation to you is to get very good at understanding the dollar value of your marketplace's rents and common expenditures.