Feel free to jump in the community here and also take advantage of the treasure of knowledge here.

@Matt GildersleeveHave you tried looking up tax info on the treasurer website?

I looked through the treasurer's site and it says that all residential rental properties must pay a tax on the income but based on the licensing matrix, I don't need a residential rental license.

@Jephney Herring  either look it up on your City or County GIS treasurer or tax map, or go to the Treasurer or assessor's office. 

I'm in port saint lucie, you said you're in treasure coast? 

As far as going about correcting it - Give the county where the property is located a call and ask how to go about that, often times it will be the Auditor/Treasurer or similar departments that will be responsible for this and they are most of the times very helpful (after all the county is loosing out on taxes by having two homestead exemptions).

What a treasure to have all that information in one place.

3) for future tax sales, what is the best way to find info. about the parcel numbers, other than the treasurer website? 

She even sends the guest a homemade video about some treasure hunt before they arrive.

The assessor (or treasurer) will tell you to whom the property tax bill is going to, NOT who the owner is.