If Wario was planned on, Sakurai would have literally said so when he discussed the other three, seeing as Wario was
also within the Top 10 alongside them.
And no, there is no legitimate source for Meowth. The idea is based around word of mouth as opposed to a direct source of information.
Now, for the topic, th
Funky or Lanky Kong would be the perfect joke character.
Funky Kong could work as well since he is the fun and cool Kong but I actually happen to like Lankey Kong the most once you get past the first three and feel Lankey would make a great addition as a fighter.
e next joke character/the next Pichu would have to be someone that's deliberately designed to be weak.
Not many candidates other than Glass Joe and Slippy Toad, who are
well-known for being poor fighters, come to mind.