Limited partner's test: (Only three test -Under temporary regulations, individuals who are limited partners and meet the more-than-500-hour test, the five-of-10-years test, or the three-year lookback test are treated as materially participating in any activity of the limited partnership for purposes of applying the passive activity rules)De Minimis RuleIf a qualifying real estate professional aggregates activities into a single rental real estate activity and the taxpayer’s share of gross rental income from all of the taxpayer’s limited partnership interests in rental real estate is less than 10% of the taxpayer’s share of gross rental income from all of the taxpayer’s interests in rental real estate for the tax year, a de minimis exception applies—the taxpayer can determine material participation under any of the tests in Reg. § 1.469-5T(a)  that apply to the rental real estate activities.

You are correct in your formula to make sure income covers expected costs.

Truthfully I couldn’t afford with of my duplexes without the rental income.

if you do it right you can get your money out (and maybe a little extra), get some cash flowing for additional income and do it again.

A structured installment sale is a highly beneficial tool when looking to exit an property (investment or otherwise) because it'll lower your taxable income and is customizable.

The resoning behind this is that while capital gains would be at a lower tax rate, the interest is ordinary income is taxed at a higher tax rate. 

I sold a few homes in Jackson MS to Naca buyers.. its a process and the homes had to be in perfect condition before naca would close  IE FHA or VA appraisal standards at the minimum.. the program is designed for first time home buyers or low income home buyers also NACA was very firm on us ( the seller) buying down rate and closing costs. 

He doesn't have any signifcant savings (~10k), and his only income is social security and a small pension which comes out to a total of ~3k a month.  

I have been renting during my whole college career and made some income through internships that I would like to use towards putting a downpayment on my first property.

First month rent for placement and 10% gross is pretty typical in these lower end markets.