Already no.18 at amazon.com in the yearly chart, if I remember correctly Smash is climbing faster than Mario Odyssey in 2017.
At COMG store smash preorder is above 3ds+WiiU version.
My prediction in the first month of release(December)
America = 4M
Japan = 1.8M
EU and Rotw = 3M
Yeah, solid 8.8M for the first month.