Just a quick update of what has happened so far:
It does seem rather simple, but it took me about two weeks to get sufficient experience in Fusion360 to get to this point.
The most difficulties I had with the nose curvature, the top of the cabin, the side panel (with windows) merging with the side and the dome that connects the fuselage with the wings.
The boat keel was surprisingly easy.
This is of course just the shape of the plane that I am implementing now. I gave up on trying to work my way outwards from simple parts (i.e. the parts that are assembled into a plane) as I kept getting in situations where I had to retrace my steps, sometimes to the very beginning.
Next up are the stabelizers, wings, floats and nacelles.