You'll likely have to evict and make sure you let the mom know to stop sending payments. 

Bob,Does that include mortgage payment or only the rent minus taxes and insurance, also you said "purchase in the same year as the home I purchase would about if purchase the next year does 75% apply or I can use all of the rental income to report?

Commercial lending was still cake (even though I couldn’t refi my own home that I owned for 12 years l, never missed a payment, wasn’t looking to pull cash, etc)Tl:dr: stay away from 1-4 fam loans and you should be fine 

Remember, you can get a FHA loan with only a 3.5% down payment. 

What could the financing process look like - what kind of down payment might be expected?

I recently used a HELOC for a down payment on a duplex. 

Trying to figure out best way to minimize down/payment closing costs.

With that said cash flow is one piece, and principal reduction on payments is another.

But there isn't a lot of calculation involved, other than figuring out what your payments would be on different principal amounts, and any widely available online mortgage calculator can do this for you in two seconds. 

Please let me know if I'm not including any expenses or missing something key.Property Details:- 3 / 2, 1374 sqft, $89k askingExpenses ($802)P&I: $369Tax: $188Insurance: $70Utilities: $50Vacancy: 5% ($62.50)CapEx: 5% ($62.50)Total Investment (Down Payment + Closing + Repair) = $25,499Rent = $1250Cash Flow = $448Cash On Cash ROI = 21.08%This is a single family home in an area where I've competitively estimated the rent (Most units running between $1150 and $1450).