He said he sent one letter stating that she had 30 days to get current or he would begin the foreclosure process. 

In the state of Florida it is fairly simple process, although you may never see the money. 

Exterior spraying I do hire.  

I was thinking of having my wife to go through the loan process and apply and see what she is getting qualified for and me as a co-signer.

We hired a developer for the latter.

I was fortunate as I worked in the largest Tax Lien Foreclosure law firm and processed many tax lien certificate foreclosures and got my feet wet as they say working other investors files. 

3) Nothing about process of how maintenance handled?

Due to item 1, adding an ADU can require years to start achieving any return (once the accumulated cash flow recovers the initial negative position).4) Adding an ADU is a slow process.

I'm considering self-management and I'm in the process of setting up systems for it.

For a 1000 unit SFR portfolio in Tampa, you could have a portfolio manager in Cleveland, OH, a call in Center in Topeka, Kansas, remote customer service team members in Mexico or (offshore) in India, and a rental payment processing center in New York.