Mario Is Missing Is Not Canon
So Mario Is Missing is not canon to the games for a few reasons.
The main reason is Mario Is Missing contradicts the current canon of the Mario games. So in the manual for Mario Is Missing it says the following. "Will the brave brothers from Brookyln permit this abominable snow plan?" This is the Mario is an Italian American Immigrant from Brookyln origin that was never stated in any confirmed canon game or manual. This is not canon to the games continuity and is only canon to the Movieverse and Supershowverse. In the games Mario is a native son of the Mushroom Kingdom and immigrated to Big City as some point.
Also, this game alongside other games like Hotel Mario is probably on the same level of canonicity as the Supershow. This is because Nintendo basically licensed the characters to Toolworks, while Nintendo's staff and even Miyamoto did not have any hand in it. Note that even games like Super Mario RPG: Legend Of The Seven Stars at least had input from Nintendo's staff like Shigeru Miyamoto. With Miyamoto saying it didn't make sense for Mario to be riding a horse and wielding a sword, but rather to be riding Yoshi and wielding a hammer. This would probably put Mario Is Missing on the same level as the Supershow canonicity wise, and the claim it's always the same Mario wouldn't apply to this game.













