I wouldn't listen to little time agents who have sold 10 deals a year for 5 years.

As an agent and investor I see a lot of newer investors make the same mistake:They saved up some cash and want to immediately buy an investment.

I'd recommend reaching out to lenders on BP (see find a lender tab) as well as asking for recommendations from your real estate agent.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

It was "not a lucrative investment" according to another agent

I'm an investor and agent, also here in Miami.

Do your research, pick a strategy that feels comfortable, find an agent that knows that strategy, look at some homes, run some numbers and then buy. 

 $500 does not seem unbelievable, but if he is his own insurance agent, he may have gotten a favor done on his own policy.

- How do I lower the expectations of the owners children (they are adults) after the previous agent listed it at Zillow's full estimated price - despite the fact that nothing has been done to the house since their father/the widows husband died some years back.

Have a witness with you (non relative).You can use a Skip Trace Agent (aka Collection Agency) to locate your "asset" (tenant).