The nose gear units puzzle me a little bit. I studied a full size Piper Cub at Oskhosh (wipline floats) one year with retractable wheels. It seems the nosegear unit rotates forward approximately 90 degrees and then slides back into the float. I couldn't see the device that locked the gear down on the nose and they appear to fully caster. The steering on the plane would then the done by brakes.

Making the floats and retracts water proof and being able to fly off the water and land with the same float will be a challenge but worth doing.