Heroes
Gamma is the star of Final Chao Egg, and sports the form of a Dark Chaos Chao. He is well-known for trying to keep from pointless babble and getting straight to the point.
Epsilon is Gamma's second son, but the first of the two introduced in Final Chao Egg. He's not too terribly bright, being relatively young, but also keep in mind that he takes a lot after Shadow...
Renma is a red Knuckles chao, being forced to live in the Midget Chao Garden with the others. What a wonderful life he leads. He is probably the most intelligent chao thus far, despite taking after Knuckles.
Named after a game series(Lunar), Lunaar is a Sonic chao, who, like Sonic, is not the sharpest crayon in the box...so to speak. He has some brainpower, but rarely uses it for fear he'll run out...
Vakura is the resident Neutral Chaos Chao, and in his experience, villainy is not to be taken lightly. Vakura is an upstanding chao, and does not tolerate being evil for a second.
Aerus was named after his ability to fly, but the name was not intended to sound like the girl from Final Fantasy VII. Aerus can fly very high, and is unmatchable in the field.
Villains
Mechanus is the first villain in Final Chao Egg. He stole...stuff...which needs to be recovered. He can create energy barriers to negate long-range attacks. Pretty tough for a first villain, eh?
EggChao is a randomly appearing villain in Final Chao Egg, and pilots the deadly "Balloon Laser Machine", for lack of any other weapons to use, save for his "Chao Rocket Launcher"... Not very creative, is he?