Thanks for explaining that. Yet, what then keeps things such as your Wario scenario from happening? That seems like a pretty big issue you bring up- that characters being unlocked along the way may push out characters from one row to the next.
The roster is designed from the beginning so that when all the characters are unlocked everything lines up in an organized roster. The devs essentially start by designing the final CSS screen. They use that roster to determine the set order of characters, and then they remove all the unlockables to make the starting roster. As the player unlocks more and more characters, they progress toward the organized roster that the devs designed.
That's why I think the perfect organization of the leaked roster indicates it is likely final. In Brawl every CSS prior to the final one is in some way disorganized due to missing characters. With SSB4, most incomplete CSS's will be more organized than Brawl's due to characters in a series being grouped horizontally instead of vertically, but there will still likely be some characters split from their series in every CSS before the final one, where everything falls into place. To be fair, there is a small chance that if a few certain characters are not unlocked that the roster could appear to be perfectly organized while still having a few characters hidden. However, there are very few ways characters could be added to the leaked roster while still making the final roster stay organized. A new Zelda character, for instance, would cause ZSS to get bumped down a row away from Samus. Since, like I said, the devs designed the final roster to keep characters together, this can't happen and thus a new Zelda rep will not happen.
The only additional characters I could come up with that
don't mess up the leaked CSS are a few specific combinations of Star Fox reps, Pokemon reps, clones, and characters from so-far unrepresented franchises. For example, one new clone would not disrupt the order, since they would just pop in with the other clones and fill the second-to-last row. Similarly, if a new Pokemon rep and Star Fox rep were both added that would fill out row 4 and would bump R.O.B. and Duck Hunt down to row 5, in turn pushing the clones to row 6, thus requiring another 2 characters from unrepresented series to fill out row 5. These scenarios are so specific that I find them a little unlikely, though they aren't technically impossible.