Adam,
You will find the water flying opportunities in Ontario much more realistic and varied than those you could find in Florida or Arizona. There are thousands of different lakes (the water filled type) around here, which offer a broad range of challenges, and touring opporunities.
I suggest that if a Lake amphib is your objective, get your float rating in that type, and avoid the float planes for now. Not to say that float plane flying is not wonderful, but you'd have too much to unlearn to transition to a Lake.
Another choice would be a Teal. tail dragger, and challenging on the runway, but great in the water (same as a Lake) and more versitile than a Lake when it comes to beaching or parking against the bottom (on the wheels in the water).
I can offer more info if you need it.
Here is one of the Teals I fly (#34), on Georgain Bay (Lake Huron)
Here is the other (#19) before paint, on a bay of Lake Ontario
