I am on felony probation for driving without license (4th conviction) I won a trip to bahamas for my children and myself. Probation does not allow me to travel outside Florida. Trip is from ft lauderdale to Nassau and back 3 days later. Will Customs get me on re-entry? Do they check everyone or is it a 50-50 chance they will stop me?

They will check even before you leave. Since your on probation then this trip is out as far as your concerned.

But it is common for the PO to give permission for travel, so as long as you have a travel pass, there is no problem.
Merely get permission from PO before you travel.