Sounds cool. I believe they would add a new (if small/niche) dimension to the game. As was already mentioned, the floatplanes could have the ability to launch from Port bases as well as Carrier Task Force groups (and, in some cases, normal airfields). The Northrop N-3PB would actually give the Ports the ability to launch fighters (albeit, slow ones).
Arado Ar 196 Light Attack Floatplane (Germany)
Max speed: 200mph
Armament: 2x 20mm cannon in the wings, 1x 7.92mm MG on the fuselage, 1x 7.92mm trainable rearward firing MG, 2x 50kg bombs.
CANT Z.506 Airone Bomber Floatplane (Italy)
Max speed: 217mph
Armament: 1x 12.7mm MG in dorsal turret, 1x 7.7mm rearward firing MG, 2x 7.7mm trainable lateral-firing MGs, 1200kg of bombs.
Heinkel He 115C/D Torpedo Bomber Floatplane (Germany)
Max speed: 215mph
Armament: 1x 15mm forward firing cannon, 2x 7.92mm fixed rearward firing MGs, 1x 7.92mm trainable forward firing MG in nose, 1x 7.92mm trainable rearward firing MG in dorsal position, 2000+ lbs of torpedoes/bombs.
Northrop N-3PB Convoy Escort Floatplane (USA)
Max speed: 260mph
Armament: 4x .50cal MGs in wings, 2x .30cal MGs (one in rear, one in ventral)
Consolidated PBY-5A Bomber Flying Boat (USA)
Max speed: 180mph
Armament: 2x .30cal trainable forward firing MGs, 1x .30cal trainable rearward firing MG, 2x .50cal trainable lateral-firing MGs, 4500lbs of bombs.