In theory a normal human being shouldn't be able to jump around as Clare and the nameless trainee did when she was coming after Clare's head. Nor are women let alone a common man be able to hold a claymore which is a two handed sword in one hand and achieve enough strength to swing it around at others let alone aim them well enough to slice clean through a youma's head. This indicates the flesh has already been implemented allowing the girls to seemingly achieve these feats without looking like a over muscular person like Guts from Berserk.
hmm okay... though i cant still believe how miata's able to remain in her child form. My theory is that the organization implants the flesh and blood only after they believe that the subject is already capable of combat abilities.
As its unidentified as to what procedure Claymores go through in order to get the implants, as I'm led to believe with the facts standing as they are, it doesn't matter which body parts they require as long as it carries blood. I would also think the procedure shoudn't take too long nor do they hesitate in operating on the children the moment they are within their grasp. I would imagine if Teresa's head was any indication, they most likely would have operated immediately not only because a rotting corpse is not the most idealistic thing to draw flesh/blood out of but because many fans would rather keep their heroic image of teresa and not as a decapitated head. Theres very limited resources we have to tell us what exactly is the procedure. My money is on blood. Because if you think about it, Clare doesn't seem to have inherited Teresa's eyeballs, or any other internal organs one can simply implement to another's body. Blood seems to be the only clean solution unless by flesh they mean a juice made out of flesh and bones after they've been in a mixer for 2minutes.
Although I ask myself "Do they preserve the flesh that will be used for the implantation?" They probably do have a way to that since thinking of it they're actually pretty advanced, probably advanced enough to do surgery.
There's no reason to believe Claymores cannot undertake the graduation exam while they are still young. Clare seemed to be as young as Miata was when she graduated and Riful doesn't look any more older than Miata is even though by age she surpass all other female claymores in existence. Miata is ranked #4 but that also isn't a indication of how long she stayed there since Priscilla was given #2 just fresh out of the academy. As such its logical to think Miata hasn't really been in live combat/service for long when she inherited the title of #4.
In Miata's case I believe the organization decided to experiment on her, trying to see what will happen if they do it on a child.
The handler seemed to talk otherwise. The yoma placed in the vicinity seemed like no accident and he did say it would be "Like the real thing". I had in mind earlier before the ES chapter 4 was out that the number of trainees most likely would have been reduced from a difficult selection process much like the RP we've had and to a degree I was right cept that the RP had numbers in 100's while in the ES we've seen at most 2 dozens. I'd wager the author couldn't be bothered to draw 100s of claymores or to keep the tradition of secrecy only fewer numbers even got to the graduation process to tell how survivability of claymores were pitifully low. In a sense you are correct about beat the other team, but the secret agenda/mission was to locate and kill the yoma in hiding than to kill each other. Organization wants only the toughest warriors to join their ranks, and as such its inevitable for them to cut down the numbers one way or another to see who is the strongest. Survival of the Fittest.
On the issue about if Claymore's aren't allowed to fight each other in training, in an extra scene I believed they were asked to form into teams right? I think (correct me if I'm wrong) that objective was to beat the other teams. The yoma that appeared was trivial to the order that was given to them which was to take out other teams in anyway possible. Of course these are only my dumb theories xD you guys dont have to listen if they seem stupid ^^