So to speculate:
The big red button is obviously "Smash", just like on 3DS. Basically like the "Group" section from Brawl.
The orange one is Nintendo Network.
The pink one is Challenges.
Then the 3DS option is obvious.
Green is the Vault.
Only ones I am unsure of are the yellow and big light blue one.
The "Solo" menu from past games actually is under "Games & More" on 3DS, as are some co-op minigames like All-Star Mode. The Vault and other stuff are also under here on 3DS, though.
It's possible the yellow one is "Solo" on Wii U, and the Blue one is "Customisation" or "Amiibo". But there's no reason to believe either case to be true.
There might also be another panel being blocked by the zoom in on the "3DS" panel.
I am hoping that at least one of those, probably the yellow or blue one, is actually a big new game mode, though, like Smash Run is for 3DS.