I have seen one bad tenant crush an entire 4 unit building with bed bugs, non payment of rent, and drive good paying tenants out of the building.The location is the # 1 priority, after that asset condition is really important.  

@David Ashworth given Florida's bankruptcy protection laws (please verify with an attorney) you may be better off paying off your primary and max leveraging the investment property for asset protection.

Why would you want to work with a realtor (I know she is your wife, no offense) who knows none of the agents, does not know the paperwork or the process (they don't teach you this in the class) when your primary residence is on the line.Brokerage options vary, but if you just choose the cheapest one and use your wife, you will pay for it later.

All four units are occupied and the tenants are currently paying their rent via cash in person.

Depending on the extent of the rehab, you can hold off on the rehab until the unit is vacant and not increase the rent as much (ie wait to pay $50K in rehab for 2 years and not increase the rent $200).

That means more or less you pay cash the day you buy. 

I’ll pay a monthly agreed upon amount to seller and have one year to pay off the full amount/find a loan.

Some just have one meter and they pay the power and if you go that route the utility cost is very high.  

In CA, that also means you're paying an additional $800 franchise tax fee per year.

I will be willing to pay a bit more to know that I can get another piece of filler stock without waiting weeks.But since I dont live in the houses I built and rent, I am looking for the most value.