As always, it may not be just 1 guy, it may be a group of people (so, more money).
I'm not sure if this is fake or real, though even if the ads are real and Nintendo uploaded them, it's still possible that they mean nothing.
The ads don't reveal the names of the newcomers, the ads only appear when you search a specific combination of words (and not even all the times), but it isn't mandatory that those characters will be playable. Who knows, maybe it's just a huge coincidence in the Google algorithm.
Also, the fact that the ad appears only when searching that specific character with that specific combination of words is super suspicious. As I said, the point of advertising is to promote your product. If only a few people will see the ad because it requires a precise combination of words in order to appear, it's just wasted money.