Actually, you may well be able to in some stores, just not the biggies. A lot of smaller stores aren't taking pre-orders, and it's strange in Japan how there are these little mom and pop game stores you can find in some places, which will just have the system sat behind the counter unassumingly.
Yup, three different ones: Shiba, Toy Poodle, and French Bulldog for JP. Don't know about U.S. but it will be more than one. What the starting breeds are for each are also not yet known.