Dumb question but shouldn't Shy Guys, Bob-ombs, Pokeys, and Birdo not be Mario characters?

[RemixDeluxe]

Doki Doki Panic was released in 1987 and Super Mario Bros 2 (US version) released in 1988. Since that game came out first wouldn't it make those enemies the source to that game rather than Mario thus not being Mario enemies? Furthermore the game was made by Fuji Television even giving more evidence of these characters not being part of the Mario universe.

Mario Sports Mix was developed by Square Enix which featured both Mario and Final Fantasy characters but I don't think anyone considers those characters belonging to the Mario universe so why do we treat the enemies of Doki Doki Panic as Mario enemies to this day?

 

[Tom Bombadildo]

Just because the characters didn't originate from a Mario game doesn't mean they simply can't be Mario characters. All of the enemies mentioned appear in just about every other Mario game since, their constant reappearance thus makes them Mario characters.

Your example about Mario Sports Mix isn't remotely close to the same situation, because the "non-Mario" characters in that don't make constant appearances in other Mario games.