Nope, not a chance unless the WiiU version launches before the NX version.

Nope, not going to happen since it is more Zelda NX now. I wouldn't be surprised if the Wii U got cancelled. Not saying it will, just saying it wouldn't be surprised if it did. The Wii U version is basically worthless.

wii u no
wii u + nx yes ofc

Nx possibly
WiiU no
Nx+wiiu definitely

No chance.

will sell now 1 mio on wii u (like TP on GameCube)
Would had sold 3-4 Mio on Wii U without NX.

Given that Nintendo is only planning to sell another 800,000 Wii U's for what is likely to be the rest of the console's life, it wouldn't surprise me if the Wii U version of Zelda U gets a very limited retail release. Both retailers and Nintendo are going to want to push the Wii U version of Zelda U under the carpet as quickly as possible next year especially since it won't be capable of selling hardware.

In all honesty, Zelda U on the Wii U probably won't even sell as well as GC Twilight Princess because of the lower install base and the fact that Zelda U won't even be able to capitalize on the Christmas sales season.  I predict maybe 1m.

No Way. It will be lucky to hit 2m, let alone 4m+

On the other hand, I'm almost sure it will on NX.

Not a chance with NX version on market, people forget that Twilight Princes on GC sold only 1.3m.
But NX version of Zelda will outsell Skyward Sword.

I think it'll tie.