I also think Metroid Prime 4 and Pokemon Switch will launch in 2018. Basically they MUST launch in 2018, Nintendo has to push their developement as hard as possible. These both seem to be the big titles in 2018. Maybe there will be a 3rd one - Smash Swich - but I dont think Nintendo will have any other really big title in 2018.
Sorry, but I dont count Kirby and Yoshi as big titles, which really will sell lots of consoles.
I have lots of trust in Nintendo, but they just can not make a new IP from nothing which is really big. I guess Splatoon was/is an exception ;)

Pokemon will probably launch in mid/late November and will be THE holiday title.
Metroid Prime 4 (at lest in US and EU) will launch somewhere around mid September to mid October - depending on what other games will be releasing in 2nd half of 2018.

If Smash Switch will be released in 2018, then I guess this one and Pokemon Switch will take the mid October and mid/late November spots, but then I am not sure anymore which game takes which spot. At least I believe both will then release within time frame October to December.
In this case Metroid Prime 4 then will take the September spot.

I don't think so, why? The last Pokemon games directed by Masuda were X&Y in 2013... do the maths.

We're definitely getting either the new Metroid or Pokemon for the holidays next year. Probably a new or "deluxe" version of Smash at some point as well.

I think it is possible. Nintendo seems to have gotten passed the learning curve of modern game development with Wii U and now they can focus on making games rather than middleware. I expect Pokemon and Metroid Prime 4 to both use UE4, which will reduce thr time spent on engine production.

Doubtful, but not impossible.

I have a feeling Pokemon will be rushed if it's out in 2018, considering Sun/Moon came out in 2016 and their second versions will come out in 2017.

This Pokemon game is going to be way more technically demanding than in the past. I say Spring 2019 is the most logical release period. I still see Metroid Prime 4 as a Summer 2019 release as well.

Wait? Are you expecting a game like Breath of the wild? No, you're going to get a game like Persona but kid-friendly and less story (which is what I want) 

I'ts Pokemon with better graphics and voice acting, they are not going to change the gameplay. I think the game has been in developing since last year with sun a moon, that would be 3 years in 2018.

Nintendo e3 2018:

Metroid Gameplay Trailer + Demo

PKMN Gameplay Trailer + Demo

FE Gameplay Trailer + Demo

Luigia Mansion 3 Trailer (Emily Rogers)

Animal Crossing First Look

Retro Game Teaser

Shin Megami Tensei First Look

From Software Game Teaser

Project Octopath Traveler Trailer

Smash Announcement

One 3rd Party Title Teaser.

Fatality.

Fire Emblem and Animal Crossing.

I'd be shocked if Monoliftsoft isn't heavily involved in helping Gamefreak with the Pokemon game. After their help with the last 2 Zelda games and the speed with which they developed XC2 Nintendo would be idiots not to have them help out on a project like this.

The recent sales of Awakening and Fates suggests it can be after all FE is now classed as a major IP so why not go further and push it as a holiday title like they did with Animal Crossing on the Wii.