I definitely have my doubts over the next gen pokemon releasing next year. That's just too soon, considering they barely got Ultra Sun and Moon out recently. It may not even happen for another year. It'll likely take some time. A smaller size Pokemon may happen instead. TWEWY 2 seems like a stretch, especially for an exclusive. Though, did anything ever come out of that 'New 7 days' tease they did long ago?

As for the rest of the rumors, not all that exciting if those are true. Gonna need more for Switch'd 2018 to be considered good.

M3 is not niche even TWEWY shifting over 700k is more than most JRPGs.

So some guy on Reddit just happens to have heard rumours from all the biggest secrets of multiple companies when no one else has heard them?

tagging, will check this out again next year.

700k is super niche.  Even a million on Nintendo DS is niche.  Persona 5 sold a million on PS4 alone,  is the best selling in the series and is well known in the industry.  And it's still niche.  Don't take it personal lads, I'm not hating on your favorite things.  They just aren't as popular as you might hope.  If they were, they wouldn't be getting port/sequel rumors a decade after release.

DB fighterz on Switch would be pretty cool. Never got to play TWEWY but Square Enix must know it still exists since they put it in KH: DDD.

A Switch port of Dragon Ball FighterZ is in the works and will likely come out in Fall/Winter 2018. Sounds legit. Xenoverse 2 did pretty good on the Switch from what I hear, so I think this one is only a matter of time.

Soul Calibur VI is in development for Nintendo Switch (alongside PS4 and PC). Link would return as a guest character on the Switch version. I buy this one too. SoulCalibur II did very good on the GameCube. Switch is obviously blowing the GameCube out of the water. Seems like easy and logical money for Bandai Namco. 

There has been pressure towards Game Freak to get Pokemon’s 8th Generation out in hopes of a release next year. If you recall Pokemon Stars, that is (or was) real, but all it was was a Sun and Moon port to the Switch, used as an engine test tech demo thing.
This one is the one I'm iffy about. I can absolutely believe that Nintendo is putting pressure on Game Freak to get Pokemon Gen 8 ready for 2018, especially after the recent reports that they plan on making 25-30 million Switch units in 2018. But, as I've said before, rushing the first mainline, HD, "console," Pokemon game out the door, just 2 years after the latest mainline games, raises all kinds of red flags for me. Unless Game Freak hired a lot of additional staff and/or Nintendo is sending some of their own dev teams and subsidiaries such as Monolith Soft, Retro, or the Zelda team behind Breath of the Wild, trying to get Gen 8 released on Switch in 2018 is a very bad idea. 
Financially, yes, it's a golden opportunity. But, critically and in terms of how the game itself will turn out, the technical risks outweigh the financial benefits, and I'd rather they take their time to make sure they make Gen 8 the best games they can possibly be for a 2019 release. I'm willing to wait an extra year and the Switch will still have an excellent 2018, in terms of games and sales, without Pokemon. 

Metroid Prime 4 should have something revealed with some in-game footage early next year from what I’ve heard. I’m hearing that Direct in January particularly. Bandai Namco is developing the game for Nintendo. I don’t know which development studio.
I can believe the part where we may get in-game footage in January. As far as Bandai Namco is concerned, the first development studio that comes to my mind as a potential candidate is FromSoftware. I mean, Bandai Namco does publish the Dark Souls series, but FromSoftware is not owned by Bandai Namco as far as I know.

There is some kind of new Animal Crossing that they hope to release next year too. Believable and expected.

The Switch’s Virtual Console will not be like how it currently is known to be like. There is some kind of a subscription service of sorts in the works. As soon as I heard that Nintendo was going to start charging for online, I immediately thought that the Virtual Console was going to see some drastic changes.  So, I can believe this as well.

Mother 3 is real. According to my source, it was completely localized and playable. The sad thing that I’ve heard is that it is being held back for some reason, which all I know has something to do with not knowing which month to release it in. Oh Jesus, how many times have we heard this rumor throughout the years? This and Half-Life 3 are the two games I constantly hear over and over again and they never come to fruition. I could suspect the entire list is BS just off this one alone. Least to say, I'm not buying this one.

According to one of my sources, they claim that Square Enix is doing The World Ends With You 2 exclusively for the Nintendo Switch.
The World Ends With You? Where have I heard that before.... OH YEAH! Somecallmejohnny mentioned it during his Kingdom Hearts marathon when he was reviewing Dream Drop Distance! Apparently, the first game was originally developed for the Nintendo DS. If this one is true... We're in for quite the leap in graphics.

Blizzard is preparing a Hearthstone port for the Switch. I’m not sure when this will be announced due to the phrasing, but I heard about this when I went to Blizzcon. Meh, don't care about this one. 

A good rule of thumb seems to be that when any rumor mentions Mother 3, then it is indeed implausible.

Persona is one of the major JRPGs and 1m is not niche and neither is a favourite of mine like someone said you're exaggerating what niche is.

He leaked the latest Injustice DLC pack which contains the Ninja Turltes a few weeks before it was announced.