Evidence and common sense. They've been working on a Wii U game for two years and TPHD is a Wii U game.

Nonsense lol. What you wrote doesn't even make sense because I'm not the one speculating. I am just the messenger.

Wind waker hd took 6 months. And there has been less work done to updateTwilight princess hd, it doesn't even have new lighting and shadows that WWHD had.

I highly doubt it. Nintendo is really anal about the quality of their work, I doubt they would just let it out of their reach like that with the story and NPCs.

http://nintendoeverything.com/tantalus-media-starting-work-on-aaa-next-gen-title-this-month-wii-u-mentioned/

Tantalus have worked for TP HD for a long time, at least since 2014. Stop making rumour by yourself.

This, it's very rare that nintendo fires people. I doubt this rumor is true

Could have been a cancelled project, that got cancelled because nintendo wanted them to make tphd. Tell me how the hell does a retexture and hd upscale take over two years? Unless tantalus is one guy working in his basement.

Something wrong here....

I've re-worded it now, the leak never said that nintendo would solely develope the game. They said that some staff that worked on WWHD will also work on TPHD. It is possible that they could be working with tantalus because nintendo does like to work with other companies to remake games like they did with hexadrive and grezzo. I think TPHD will not solely be a tantalus developement, Nintendo will have staff helping them. 

TP HD has more complex textures than WW. Retexturing those all texture might not be so "difficult", however, it can be some kind of works taking time.

Also, it can be though Tantaluse finished their job already, at some point in 2015, but Nintendo decided release it at 2016, because of lack of titles.