Prior to the official announcement of Yoshi's Crafted World's title, a fake leak was posted on 4chan listing off future Nintendo games, containing the title of Yoshi's Crafted World. This leak was humorous in nature, contrasting legitimate sounding titles such as Animal Crossing: Town Founder and Paper Mario: Clay Catastrophe with obvious jokes such as Metroid: Equestrian Races and Rhythm Heaven and Hell - this lead to a short-lived theory that the leak was indeed real and slid in the joke names for humorous effect. Over time, reveals of installments in other franchises featured in the leak that didn't line up would show that Crafted World was simply a lucky guess. However, some other articles from the leak, such as a multi-part DLC pass for Mario Kart 8 Deluxe, Pokémon Diamond and Pearl remakes, a Tokyo 2020 Mario & Sonic Olympics game (albeit without Pac-Man), a Switch port of Overwatch, and the at-the-time-believed-to-be-cancelled Pikmin 4 would come into fruition later by coincidence.

As a throwback to the original Mario Kart Wii version, if the player falls off the Wii Rainbow Road stage, the character and kart will burn as they briefly enter the Earth’s atmosphere before Lakitu rescues them.

This marks the only stage in the entire game (including the original Mario Kart 8) that has this property.

Piranha Plant Cove is the only non-city Tour course that has more than one layout.

Aside from the RMX stages that appear in the original game, Piranha Plant Pipeline is the only Tour stage absent from the Booster Course Pass. This was most likely done as a way to avoid confusion with the pre-existing Mario Kart 7 stage Piranha Plant Slide, which contains many similarities to Piranha Plant Pipeline.

The Koopa Troopa shell bouncing between the pipes of the Wii Koopa Cape’s starting gate is a reference to a Koopa Troopa’s behavior when Mario/Luigi jump on, kick, or throw a stepped-on shell.

An unused emblem for Kamek (or an unnamed Magikoopa) appears within the original Wii U version's files, suggesting he was intended to be a playable character at one stage during development. Kamek would later be added as a playable character in Wave 5 of Mario Kart 8 Deluxe's Booster Course Pass.

In the Spanish Official Nintendo Magazine, a picture was shown that included Diddy Kong in the cast of characters, suggesting that he was a planned character for the game, but was cut. Diddy Kong would later be included as one of the last four characters for the Deluxe port’s Booster Course Pass, nearly a decade since the original game’s launch.