The recent Direct has reassured me that Zelda is probably still coming to Wii U, but I'm still not 100% confident.

Does anyone else here still harbour doubts, or is this just me being my usual paranoid, pessimist self? XD

I'm going to be so pissed off if it's not going to come out on the Wiiu! I'm not planning to buy the NX until it has a good enough library of games.

No single doubt, I am 100% confident that is coming on Wii U.

Zelda U is biggest game for Wii U that is announced basically on launch of that system, that is confirmed almost for that system every time when game is showed or mentioned, game that was already shown running on that system, that was again confirmed just few weeks ago and game for which hype of Wii U owners is huge.
I think there is not a slate chance that Zelda U will skip Wii U.

Zelda U will come to the WiiU. Nintendo can afford making a port or a remastered version at the start of the NX lifecycle (either like TP or like TLOU), but not skipping the WiiU. They would be burnt at the stake by WiiU owners.

I don't have any doubts.
The game is planned for release in 2016. We won't see a new Nintendo home console before 2017. So on which platform else should release? It can only release on the Wii U.

No it is coming out on WiiU. Nintendo would be the biggest asses if they still moved the game completely from the console after reassuring everyone about that fact many times over. I think it'll also come to the NX though, whether by "TP-ing" or by "TLoU-ing" (these should be standard gamer-speak now ) .

Twilight Princess came to the GameCube ... albeit Nintendo gave GameCube fans one last kick in the balls by making them wait until *after* the Wii launched to play it.

I could see Nintendo doing that again and/or pulling something else like making the Wii U version of Zelda U digital only (or the retail version being extremely limited) citing a need to move all Wii U storeshelf space out in order to make room for the NX. 

If it didn't, it would be the biggest PR disaster in gaming since Xbox One at E3 2013. After several confirmations from several people at Nintendo and a recent trailer tease, there's just no way.

Dear Lord, I didn't even consider that...

I don't doubt it will come to Wii U, however I do not believe it will be Wii U exclusive. I believe we will see an NX version much like the Twilight Princess port(?) on the Wii as a launch title.