Onetack,
They would always take off into wind, just because its not noted in one book doesn't mean it didn't happen. A fully loaded Cat with a 10 kt tail wind simply wouldn't happen.
As to one PWC changing course.... Go around! It happens all the time, not a big deal. Floatplanes always get a great look at what the boats are doing and change the landing area to suit before the landing that exact time. A fully loaded Van will only need about 400 meters to stop anyway so if you can't find that I would be very surprised. I doubt they will mark the landing area with markers there is just no need.
As I said PERTH this is not a new thing it has been going on for almost 100 years now there is no need to reinvent the wheel... arhh float.