Gertrude, I love your story! combines all sorts of hazards into one single flight....you have tried ridge soaring in a glider, I hope! having one's family on board is always a stress test.
I got my seaplane rating at Jack Brown's in Florida, highly to be recommended and lots of fun in an uncomplicated J3. As the home lake was a bit small, takeoff speed was achieved by going around in circles. Worked eventually.
Most lakes in Florida are OK to use; but EVERYTHING ELSE has the right of way. That includes swimmers, boats, birds, aligators...because they have no idea what a floatplane requires, so they won't give way...probably won't even notice you. I particularly enjoyed the glassy water approach and touchdown. Its useful on other surfaces as well.
But when they hand you the license with the endorsement, one still is not permitted to take the J3 away solo; gotta go buy your own! or go to Canada...