It has been mentioned by some that there is a distinct pattern and reason for the names of Sonic characters in the different series that exist. Obvious ones such as Tails (for his two tails) and Knuckles (for the strong spikes on his hands) exist. Others such as Cream (light, sweet and innocent is a brief description, even though this one appears mainly to be a joke on "Cream and Cheese"). Even when American's make something involving this franchise it tends to bleed over. For instance, "Rotor" from both the SatAm and Archie series is a mechanic, hence the name fits rather well.
So the idea of "fitting" themes is not a new one in the Sonic Franchise. But what about adaption to the original design? Or better yet, conscious idea when the designs were originally established. Essentially, each character was built for more than just their main ability or their name. The physical structure as well as internal lends each character their own abilities and personality. The following are a few examples:
Sonic: First and foremost he is built for speed. That's obvious just by looking at him but how else is he built? His arms are shorter than his legs, which are also rather long. The scientific build for a perfect runner includes short arms, long legs, and a backside for balance.
Sonic also has a tail which aids to keep him balanced while his legs push him along. SEGA's remake image of Sonic for the newer systems also highlights these features.
Some people might believe it silly that Sonic can fall from such a massive height without injury or, in some cases such as Sonic X, take massive amounts of kinetic force against him and still survive. When considered this is almost plausible based on his design. Sonic has broken the sound barrier before. Most people who tried this before the proper design for doing such a thing exploded. Sonic's structure is built to withstand massive amounts of force placed upon his body.
Tails: The design here seems obvious, "he has two tails which let him fly." But it goes beyond this possibly. Tails is a lightweight creature, probably about the same build of Cream (also a flyer). His small body mass makes it easier for his Tails to support both him and something else. In addition, his small body requires less oxygen. Less oxygen means that he can fly at higher altitudes in an open cockpit with no problem. His lungs are obviously powerful as he is able to breath even at fast speeds without any problem.
Knuckles: While very similar to Sonic, Knuckles does have a few distinguishing characteristics. For one thing, his chest muscles are larger. In most images, whereas Sonic is pretty much uniform, Knuckles has a chest (in reference to the other Sonic characters, Big and Eggman excluded) like William T. Riker off Star Trek Next Generation. Most of his power is in his arms, which is amplified by strong pectorals as well as the arm muscles themselves. Even in drawings his body appears to be "stockier" than that of Sonic. An obvious way to draw him since he is supposed to be a strength character and not an amazingly speedy character. Yet even Knuckles has some speed. His body is also designed with about the same style as Sonic's, lending it to be a fast moving character.
Now this idea has its limits. Not every character has some deep meaning to them as far as I can see. Amy has no special powers except blind rage but then again her name doesn't reflect her character very well either. So while this point matches several kinds of characters it doesn't apply to all. Exceptions to the rule always have and always will exist. For now it seems that the most important characters will be matched with more than just a name=ability style.