It's a floatplane, but:
1. Just fly on land and no seaplane rating needed.
Really...??? I asked a seaplane examiner that very question and the definitive answer was NO, you can’t.
His reasoning, perfectly sound to me, was that once it floats it is no longer an SEP(land) and you don’t have a class rating for SEP(sea).
Be interested if you can point to chapter and verse under the EASA regs to prove one way or another?
DD
(I do like your thinking, though!)