With the knowledge we have right now, I am gonna say that it'll be very niche. So, in clear cut terms, no.

I think it'll be very successful. The handheld market is going strong for Nintendo since the mobile game market is as stale as it can be. Enough power to run more demanding games and an interesting concept and you have a recipe for success.

200 million minimum.

At 200$, and if include also pokemon, monster hunter, i think it might have a chance.

I think it'll be moderately successful, with sales around 30m or something maybe. More successful than Wii U, but probably less successful than 3DS.

This is the end of the traditional handheld. Once the Vita and 3DS get discontinued, there will only be this hybrid or mobile, but nothing else.

Nintendo will be successful enough. 60m units shouldn't be that hard to reach, and then make money due to their insane attach rates.

Eh, I don't know.
First of all, the music in the video was not my cup of tea and annoyed me quite fast.
I am not convinced from the concept in any way. The screen is way too big for me and I think in the end, it tries to be a lot of things but does nothing right.
It doesn't look good to me, either from a performance point, nor from how the console and the handheld looks.

Depends on price and marketing. And remember, this thing is BOTH a handheld and a console. So it has the advantage of taking your games on the go and being able to play at home. This thing doesn't look like it'll be a hit with western 3rd parties but the Japanese are going to tear this up.

I mean probably to a degree yes. It's definitely not going to be a Wii or DS, there's nothing new here that's mindblowing, it's basically a revamped Wii U. But possibly can sell about 50-60 million *if* Nintendo does a lot of things right and their portable market doesn't shrink any more (but these are big ifs, a lot could go wrong here). 

Depends on how many kids they can convince I think to carry this instead of a generic tablet or iPad. They need a new IP to really take off or for Splatoon 2 to be a huge deal. 

110% depends on the price but I think it will