If you want both a beautiful and challenging area to fly and the best diving in the country you should go to Vancouver Island.
If it were me I'd go to Campbell River. Diving is great - try Abysal or Dynamike charters on Quadra Island. Parallel Aviation does seaplane ratings and 50hr courses. I hear they are ok but I don't have any personal experience with them.
If you want the best seaplane training I'd go to Ft Langley Aviation. But the diving around the lower mainland is soso compared to Vancouver Island although day trips around are pretty easy...