Proven... In Smash Bros.? Because while that states it for the convenience of transforming the character model, Meta Knight has thrown off his cape in actual Kirby titles to reveal his wings (a memorable example is RtDL).
Perhaps originally, but... He's totally noodle-armed. Guy needs to stop skipping arm day. Like rly.
And he has thumbs.
Human babies tend to have all their body parts grown enough when they are born. For Kirby to grow fingers later is... Bringing up a very disturbing line of thought, so no. Somehow his blob hands can hold weapons, so I think he's good.
YOU FORGOT THE FACT THAT HE IS THE CUTEST EVER
It's been confirmed
I has the stupid
I think "does Kirby have thumbs" is pretty simple imo. Go piece together Skyrim and get back to me when you're done.
Mario doesn't need a timeline, superimposing plot (at least outside of paper mario), or any sort of macguffins to advance story - only gameplay. There's a simple simplistic Kirby timeline, though - the order the games released. Nintendo has only excluded minigames and spin-off bigger versions of minigames or etc., although most general spinoffs try to stay coherent.
Kirby games are masterful puzzles within themselves, and aside from familiarity and chronology they don't force it on future titles.
Look, Kirby gets attacked by a bunch of space pirate mice stealing his cake and accidentally release a dark star who does evil. Boom, plot of Squeak Squad done and over with.
It's not that hard, really. Disregard the anime and theories are very scarce.