Since Adventure mode can, in theory, be completed with 2-4 people, I'm just wondering who'd be the joint first to put said theory into practice.

Adding 2 player co-op would be cool, only in the any% category, otherwise, there would be too many categories. (In 3 and 4 player mode, you can’t play K0, so to beat the game, you’d have to leave 3 and 4 player mode.) btw a really golden tip in Golden Muttley mode: if only Player 1 collect all 10 Golden Muttleys the game will still give the star and the clock, so player 2 doesn’t needs collect any golden muttley. However, Player 1 MUST win in first to this work, and Player 2 still must win in second. This makes Golden Muttley easier and saves time :)