The WiiU will be stone cold dead in stores by the time this releases. This may not be the final delay either. It does seem at least reasonably probable that the WiiU version is dead. Pre-order availability means nothing, that's been proven countless times in the past with cancelled/delayed games and games that changed platforms.
The architecture of U vs Switch is utterly different as well, so if they never finished the U version completely the way they wanted, they may have shifted all efforts to the Switch version, and are softpedalling the eventual cancellation of the U version altogether.
Come to think of it, it would be outright bizarre to release the U version so long after the system is dead in the water. It would be like Microsoft releasing a major Halo/Forza on OG Xbox in 2006..







