Like @Russell Brazil said there are general things that need to be in place.One that stings a lot of people is the main entrance door.

I am located in Maine and have 2 six unit buildings, 2 four units, and a 5 unit. 

The property has 7 acres with a 3/2 main house and a second separate 2/1 house (which also needs renovation) with its own drive.  

Main reason why I am a little skeptical is because I have had experience with companies that offer to find a "best lender" similar to bankrate.

If one or more units are vacant, the remaining units often don’t provide enough cash flow to cover expenses, making it harder to meet operating costs.Maintenance costs: A fourplex comes with four times the appliances, plumbing, HVAC systems, and other components to maintain, leading to significantly higher repair and maintenance expenses than single-family homes.If you want to see the detailed calculation, read this BP blog - More Units Doesn’t Mean More Money—Why a Single-Family Home Can Beat a Fourplex.Resale value: Multi-family properties have a limited buyer pool—mainly investors—who base their offers on CAP rates.

We’re moving into the ADU ourselves starting in January so we can remodel our main home.

While not my main area of practice I represented a Brooklyn credit union lender, some buyers/sellers and a few landlords in real estate transactions and rent arrears cases.While we had successes and some failures along the way I ultimately concluded that I wanted to do something different with my life and cashed out of the business.

But your main killers; road access, water access, fire hydrants, flood plain, storm sewers, Storm ponds, road surface requirements, etc. 

Keep in mind the 3 main ways you make money (cash-flow, mortgage pay-down, and market appreciation). 4.

Parking will likely be your biggest hurdle.