I don't think they're using their actual bodies. I think when they're revived the boy just takes on the appearance of their original bodies. I could be wrong. And after he revived Deidara, people are asking about the body parts... Edo tensei = regeneration. Hence he's in one piece even if he was revived in parts...
And all Kabuto needed was DNA. Otherwise he would have had to dig up Madara's body. Along with all the Kages.