I don't know, I wouldn't trust a random magazine in Spanish, unless it had definite information from Nintendo.
Dear Wii, you do not know what a sequel is. There are many sequels to games, books, movies, and other things, that are not the original title with a 2 added on. Examples: Chrono Trigger, followed by Radical Dreamers: The games are vastly different, but continue in the same story. In an alternate timeline, there's also Chrono Cross to follow Trigger (similar to Super Mario [something] followed by Super Mario [something else]). Or the Star Fox games, Star Fox 64, Adventures, Assault, and Command. Each is a sequel to the one before. They do not all share the same gameplay mechanics, nor do they have any sequential numbering system. In more radical sequel-naming, we have the plays The Barber of Seville and The Marriage of Figaro. (Yes, they were plays before they were made into operas). The latter is a sequel to the former, and it is not called "The Barber of Seville 2". I can find lots more examples.
You say that a sequel is "like another game before it in some way". Well what do you know, Super Mario Sunshine is like Super Mario 64 in a lot of ways. But that isn't all a sequel can be, since many games carry on the story started in another game, yet play completely differently. If I must, I will find examples to demonstrate to you.