You would want to factor in for vacancy and repairs.

If they can get vacancies down from 5 to 3%, big impact on NOI and ability to refi.

The risk of vacancy is slightly higher than a typical rental however this can be lessened with contacts with different agencies hired to procure housing.

If you're a high earner making several hundred thousand a year and can easily cover unexpected vacancy/expenses, vs someone who is highly leveraged with little margin for mishaps, the answer would be very different. 

I am unsure of WHAT numbers to crunch aside from taxes, rent, maintenance, accounting for vacancy, unsure about cap rates, etc.

Multi-family is sparse, as there aren’t many Multi-unit properties in town, but single family homes have pretty great returns, lower purchase prices, low insurance, and low vacancy.

If it's really in the kind of neighborhood that see that kind of cap rate, management is going to be a nightmare and you should probably triple your vacancy expectations.If you're really going to add this kind of value, I expect you'll have to completely re-tenant.

Buy 4-5 houses make more money over the long run, but run into the risk of having to cover mortgage payments if there is vacancy. 

Bachelor/Hood, great microbreweries, diversifying employer base, and low vacancy rates.

I always felt I could acquire a report from some real estate data company and I would have a better feel for prices and vacancies, but I can't seem to find a service that readily provides this information.