This may seem bold/crazy but I think the updated ports of Mario Kart 8, Smash Bros 4 & Splatoon will each sell higher than their Wii U originals and will each pass 8 million.

Nah thats too much. But i thinl each will do 3mil easiily.

Splatoon can do upward of 5mil if japan catches on

I have my doubts about that, because I think Nintendo will try to have a Splatoon sequel around its second or third year, so not much time to reach 5m. Unless the Splatoon bundle really gets pushed and sells a lot through that.

Ugh, that's actually tricky to predict!

MK8- 3-3.5m
Smash-2-2.5m
Splatoon-2-2.75m

If Mario Kart has an attach rate SO HUGE, this mean that the only reason it isn't selling more is because the install base can'd concete it to do more.
A port of this game in another platform, wuth of course a bigger audience, will definitively sells massive, and i would not say is so crazy expect more than the Wii U version.

Same for Splatoon in Japan.

Smash is a difference story, it already have Wii U and 3DS version... i think it will be the port with less sales, though i still expect it to be massive. Alright, i'll say my predictions:

Mario Kart 8.5 = 8 million
Splatoon 1.5 = 5 million
Smash Bros Switch = 3.5 million

So this would put all games at:

Mario Kart 8 = 17.5 million (9.5m Wii U / 8m Switch)
Splatoon 1 = 10.5 million ( 5.5 million Wii U / 5 million Switch)
Smash Bros 4 = 18 million (9 million 3DS / 5.5 million Wii U / 3.5 million Switch)

Not unless they are given away for free or bundled. How do you even know if the Switch will be a success? Might sell worse than the WiiU, might sell better, who knows.

Ill give you a prediction:

They will sell better than new third party games. Leaving developers and publishers even less interested in Nintendo consoles.

Well, that of course depends on how well the NS has sold by the day they are released and how well are publicized, also how attractive they are according to the improvements they offer, but of course they'll be multi million sellers.

Well evre of those games can hit at least 5m expect Smash Bros because already is available for 3DS and Wii U, but even for Smash Bros I seeing hiring at least 3m.

You're right, this is assuming that Nintendo is successfully able to consolidate their handheld & console audiences.