But the only DNA evidence implying he was on the plane is the blood. If they literally test any of the other bodies they will notice he's none of them. They aren't just going to say 'this is Pavel's blood, despite the fact that multiple people can have the same blood type. He's dead. CASE CLOSED'. They're going to check to see if any of the bodies are actually his.
If they "literally" test any of the other bodies? I don't even... what?
Okay, quick refresher in high school biology: blood type testing takes minutes to do. Stick some antibodies in a sample and watch it coagulate. You can do it in a dish in any high school lab. It also tells you jack squat, because there are only four types of blood in the world: A, B, AB, and O. So yay, you get part of it right, because there are indeed many, many people in the world who share the same blood type.
But NOBODY is saying "case closed" after that. Because NOBODY USES BLOOD TYPING AS A MEANS OF FORENSICS TESTING. You know why? Because it's NOT a means of forensics testing. It provides you with no information beyond "oh I'm a type B, when I go for a blood transfusion don't give me type A, or I'll coagulate." Blood typing, as people have pointed out many times already, is not the same thing at all as forensic DNA testing. (Which, incidentally, has a turnaround time of... I believe at least a week, by general trade standards. So you see what everyone has been saying about the blood transfusion being a means of buying Bane extra time to get Dr. Pavel Stateside? Yeah. CIA would be faster than a week, I have no doubt, but it still takes time.)
Yes, dental records are a better means of ascertaining identity. There's some truth in television: bones in general are better than tissue for that sort of testing, and it's also liable to survive a greater degree of trauma (tissue would probably have sustained too much damage to be viable in any sort of testing). Yes, the CIA could very well find bone fragments that would contradict whatever evidence the blood sample might give, once they really attempt to match up every presumed body on board with every blood sample and every tissue sample... but it takes TIME to do. Indubitably the CIA would perform a thorough investigation of what led to the crash, even without the suspicious twofold connection to Bane, but by the time they have conclusive evidence... where in the world would Bane and the reports-of-his-death-have-been-greatly-exaggerated Dr. Pavel be? Long gone. THAT, I think, is the point that we're all arguing around right now.