Well, your comparing to a game which the console sold half of it ( Wii U: 9m+ PS4: 21m+ )

I think it will outsell both, although not by much.

It all depends on the reviews.

will outsell both as long as they dont port sunset overdrive to pc

I think it can but don't expect it to do it right away, it will leg it out though. The order legs were cut due to poor reviews and sunset because xbox fans didn't support it enough.

With the push of the game, the testfires and high quality of the game, I think it very well could sell more than either of them.
I can very easily see this game selling over 1 million. It seems to have mass appeal, especially after you play it.

Hard to say, I think it could outsell it but only by a slim margin.

Welp, this dumbass thinks Splatoon will get 1mil By end of June. Be easy on him XD

http://gamrconnect.vgchartz.com/thread.php?id=202929&page=1

No.
The problem with any Wii U game is that Nintendo cannot sell the console they play on. Splatoon will not change that fact.

Doubt it.

Also don't forget that by the time Splatoon releases, there's going to be 2 more months of sales for both SO and The Order.