[tl;dr]
You can't call a minor detail in Cave Story right or wrong unless it was part of the game's dialogue itself. Hell, you can't accurately define ANYTHING that takes place outside of the dialogue itself even by pointing it out from the most believable standpoint. Pixel left all of this up to the player's imagination (and last time I checked, my imagination as well as the creator's wasn't being held down by any voice of logic or reason) which is why you notice a lot of diffrences on the details of fan art (such as the one linked to yesterday).
There are no accurate details on unimportant things such as the height, skin color/hair color/eye color of certain characters, what world the game takes place on (because it doesn't take place anywhere but a nameless floating island above a namless stretch of planet, as Pixel himself has stated in diffrent words, leaving you yourself in charge), what Balrog is, etc. The list goes on. Everything that was skipped in dialogue is dependant of the player's imagination, and nothing can prove or disprove it because it's
all imaginary. Saying anyone's take on a detail in Cave Story is fact or not, despite any flaws or odds, is not only flat-out untrue, but can come off as offensive.
All that crap aside, I was never trying to prove or disprove, agree or disagree with anything, since you can believe what you want to about Cave Story and shouldn't need to be told if it's right or wrong unless it's been absolutely confirmed within the game based on any perspective. I just can't see why this was not cleared up, and I apologize if I've swerved off the topic completely.
[/tl;dr]
Something about mimigas, transformation, and clothing?