The way it looked at the end of the chapter, when pein summoned those two, it looks they could be hidan and orochimaru, it might just be their bodies being controlled by pein. and about the whole destined child thing, maybe the prophecy had like a second part to it, maybe the old frog forgot to say it.. it is kinda foreshadowed when the other frogs say the old one is really forgetful, it is also foreshadowed that he forgot something by the way he acted, he had a very bad memory. So the second part of the prophecie might be about how if the chosen child turned evil, there might be a person who has to defeat him.