Well if you want Mango and you want the best, you're looking for Nam Doc Mai and it's available at Pine Island Nursery
This is their website:
http://www.tropicalfruitnursery.com/...ewer/index.htm
It may be a little bit of a drive as they are a bit south, but well worth it.
I'm not sure if they have coconut but as far as exotic fruit goes they are one of the best in the world.
You might also want to give these guys a call and let them know you are in town from NJ and ask if they will let you stop by.
http://www.rfvcbroward.org/ (click plant list on the left)
I have not met them yet but have been meaning to take a trip out there... it's not even that far from me just haven't made the time to visit or join.
Spikes Grove is another you might want to visit, they are off the turnpike, in Davie. They have a little of everything, not too sure about heliconias though... shoot me a PM if you want me to get you their number, I'm sure I have it in my filing cabinet..
I'm probably forgetting other must visit places and so I may update the thread with some more
Enjoy your visit!