I was trying to respond to the comment of why the akatsuki even needed the tailed beasts in the first place if Pain could just do it on his own. If they weren't captured before, it would be a lot harder to wipe out villages using his methods. People would also be a lot more likely to oppose Akatsuki if they have a tailed beast.
As far as the bodies...I always thought that Pain ressurected the dead bodies and then controlled them through the rods, so they're not just puppet corpses.