I don't know how valid that claim is, besides the fact that the character files are most likely empty. Sakurai stated...
"Speaking on the development of the character roster, Sakurai said that most of the characters were settled upon in the planning stages, which was completed about two years ago. But Sonic was the exception to this process.
"The decision to include Sonic was not made until 2007," Sakurai noted. "
Sonic seems to be the only exception, from this excerpt of the article here
http://www.destructoid.com/gdc-08-masahiro-sakurai-talks-brawl-development-71767.phtml
Another point is..what evidence do we have that suggests Brawl uses Melee character files? Why would they 'have' to use Doc, Pichu, Roy, or Mewtwo's files in a new game without any content related to them?I could possibly see them using their model for trophies...now, I'm not knowledgeable about the trophies in Brawl, but doesn't the Mewtwo trophy use a different model than the one in Melee? I had thought Brawl was designed from a new engine, rather than an updated Melee engine?I could be wrong, but nevertheless...
I believe my reasoning still stands. If the initial roster was determined in 2005-2006, and the only character added later on, Sonic, is still actually in the game...why is it that seven characters got the cut?If these characters were cut, why do their files still remain in the game?Even more curious, why are these files EMPTY at all?That suggests that the data for these characters was either deleted, somehow relevant to the operation of other features of the game, or intended to be filled out at a later date.
If case A, deletion, is correct, why delete the data for said characters yet leave a placeholder with their name in the character files?It makes no sense..one could argue that 128 bytes (?) is negligible, but still...logically they'd delete the placeholder as well.
If case B, a dependency on these files by the game somehow, is correct, we may never know for certain.It would require the source code for Brawl, or hacking of the files...Getting the first is unlikely, and using the second would take a lot of time and effort for something that would likely bear no fruits, so it's a labor only for the bored, curious, and technologically inclined.
Case C, however, seems the most likely logically, but has been denied in some aspect by the game designer himself.
This may be a mystery we'll never know the answer to, but one thing is for certain: The pieces of the puzzle we have now don't seem to sit quite right at all, at least with me.