I'll make another completely hypothetical non-leak first party launch lineup again.
Zelda BOTW
Mario Kart 9 (could be launch window but it's pretty darn close to fitting the average Mario Kart release cycle and I can see Nintendo wanting to get it out ASAP)
Animal Crossing (they could patch New Leaf to work with the app but it's been a while since the last mainline game and it's another thing I can see them wanting to get out ASAP)
Splat2n (I have NO idea considering it's made by the same group that handles Animal Crossing, but the time between the seeds of the concept and a functioning demo for the first game was darn QUICK and IIRC it might be a slightly different group of people than the usual Animal Crossing staff that works on it, so I'll throw it in the pool just in case.)
Pikmin 4 (Not sure on this one, it could be launch window since it was put off in order to work on something else, but it was also "nearly done.")
Retro title (Not likely to be DK or Metroid, but they have SOMETHING in the works that's been in progress since Tropical Freeze wrapped up so it's likely to be a launch title.)
It doesn't match up with Nintendo fan fantasies, but if something like this ended up happening then the launch would be absurdly solid compared to usual. There's a decent genre spread in there. The first four also all are from series that sell like freaking candy, which Nintendo said they were aiming for so that they could support themselves in the event that some of their games fell flat.
Mainline Mario is unfortunately Holiday 2017 at earliest due to what was said about it, but all of these titles may or may not have something happen due to how their developments are doing or have done in the past.
I also expect some surprises, but being surprises I obviously don't have the faintest clue what they might be. These are just the titles I can easily see being possible, and it's still a bigger and higher profile launch list than I expect most people to specifically list in leaks or generally speculate on.