Law must be different in FL, tax records are public domain here through the country auditor's office. I think you said you have friends who are realtors. Ask them to do a MLS search for the address. That will at least tell you how many times/how often the home has been on the market/sold and when it was first placed on the market.
The FOIA requests to police/fire departments is most likely to determine if there's anything negative relative to the property address. Calls for murder, spousal/child abuse, domestic disputes, alcohol/drug abuse, etc. would be a strong indicator things are/have not been good there.
There's always talking to neighbors who've lived near the property for a long time as well.
Another route might to contact a local paranormal group and asked to be put in touch to their researcher. They would be more in turn with local/state law and could offer suggestions on what's available where.