Bomberman and puyo tetris haven't sold 1 million. The publishers haven't said it reached 1m, there's no link that said it sold 1m and according to vgchartz both haven't reached 1m. Mario + rabbids isn't a good example of 3rd party

All of Nintendo's first-party games that aren't ports will sell at least 1 million. I also think Octopath has a chance

https://mynintendonews.com/2018/03/30/super-bomberman-r-sells-one-million-worldwide/

http://www.topesko.com/2018/03/super-bomberman-r-broke-one-million.html

Puyo was closing into a million in the beginning of February, so even if it hasn't crossed it yet, it still shows that your statement that a third party game can't get to a million is false 

That's weird. I did search and only saw they said it was approaching 1m on the 30th of march 2018

I guess it's going to be more than 10 from now on if we count games released last year that make it this year:

Skyrim, Smash, Kirby, Fire Emblem, DK and Yoshi are all guaranteed 1M sellers, add to that Pokémon (which isn't confirmed for 2018 but will soon) and you need 3 more milion sellers, and that's excluding Octopath Traveller just because it's a new IP

Got to be over 10 if titles from last year are included. FIFA, Skyrim and i'm sure a few others, plus both LABO kits, Kirby, Smash, Yoshi, Fire Emblem, probably 3 as-yet unannounced titles from E3. Whichever title is holiday title. I'm also expecting pikmin to be announced for a July or August title. 

EDIT:- Oh yeah and DK, Mario Tennis and maybe Captain Toad and Octopath.

The articles saying that Bomberman R had crossed the millon mark came at the end of march. The problem is that nowhere in the articles said that that was the exact date of it reaching the milestone. That's why, on the 1st year million seller list, Bomberman R appears with question marks. I don't know whether it did it or not, but for the sake of convenience I put it there.

This is tricky by nature and all we can do is venture a guess. So here is mine:

I think the Switch will calm down a bit in sales this second year, the only "big gun" left to be released now is Metroid Prime 4

This first year it sold what again? 14 million units, give or take?

So I will go with 9 - 10 million units this second year. Less does not seem realistic as the Switch definitely has traction. More is possible if other big guns appear.

Let's wait and see what the real figures will be. But I say 24 - 25 million Switches sold in total by early March 2019.