Perhaps I've misunderstood you. I thought you were saying that you now believed that you'd like to stay on Ambergris Caye and not Caye Caulker because your son would like to be where the action is.
Of course, Pedro is not Chloe and certainly anyone reading your messages knows that fishing is your big desire. If that really is all you are about then Chloe's advice about El Pescador was right on target.
If you just want a clean place to stay and book your own fishing, that can easily be accomplished too, from either San Pedro or Caye Caulker.
Help us to help you. Do you want to stay near San Pedro Town so that your son can be near where the action is . . .or do you want to forego all that and dedicate yourselves to fishing? Do you care if there are a number of good places to eat (San Pedro) or do you only need one or two places (Caye Caulker)? What budget range are you looking in for acco?