Not the first, but probably the only cantilever-wing other than the Junkers F13, was the Fokker F.III, first flying Amsterdam-London on 14 April 1921, piloted by English pilot Hinchcliffe. Its fuselage was constructed of steel tubes and covered with fabric, and the wing was made entirely of wood, the outer covering being plywood.
The Junkers was of more modern construction, using corrugated duraluminium for the skin and an aluminium support structure. Both Anthony Fokker and his factory GM Reinhold Platz were more focused on quick and practical implementations, and were helped by the restrictions that the allies placed on the Junkers engine capacity.
The pilots of the time obtained a lot of fresh air. Fresh as in not very warm, since the fumes of the 230 hp Armstrong Siddeley Puma engine were not very far away from the pilot's face. Here is Anthony himself in the cockpit.