February/March could be Metroid/FE. Main spring game in April.Even for a show that promises to focus on 2017, I don't think it's beyond Nintendo to tease one big game for "first half 2018" and another one for an unspecified slot in 2018. It's worth keeping in mind that the spring release calendar is often headlined by a mass-market-friendly title (think of precedents like MK8 or Splatoon), which Metroid (for instance) wouldn't be, although we did get Star Fox Zero last April in what was a very quiet year.
And who knows: maybe Nintendo will call on Retro to provide an answer for the multiplayer co-op shooter market occupied in the west by Destiny, The Division, and Anthem. Maybe something leveraging a well-known existing IP. How about this: the players are all ground troopers in the Galactic Federation...
As to the hypothetical: . But it could be good for others.