I had pretty much the same thoughts and eliminated any of the smaller biplane trainers such as the Fleets, Stearmans and Tiger Moths as likely possibilities. Even a Cornell is an unlikely candidate as it was a mostly tube and fabric trainer that would be pretty well decomposed after 60 years in salt water, but it loosly fits the two seat fighter looking description.swankenstein:When I was in the war, the trainer I flew was the 2 seater Tiger Moth, but I doubt any of the ones I crashed would have survived this long underwater since they were made out of wood and fabric.
I am also thinking the Vought OS2U / Kingfisher I could be a good candidate. It saw duty almost exclusively on floats in the US Navy but I am pretty sure it saw much more extensive service and coastal patrol duty with wheels in British and Canadian service. It would be a two seat aircraft with roughly fighter size and looks.