For those who say "Orochimaru couldn't summon the kage's because they are in the death god stomach"
No need for manga pages....Simple logic:
-Yondaime was already in the death god stomach from sealing the kyuubi, then Orochimaru tried to summon him in the third coffin. He got stopped by Sarutobi.
So if there were ever to be Pain VS Oro, Edo Tensei will put him in his place.
Orochimaru + Shodai + Nidaime + Minato. If Jiraiya himself can knockout 3 of them out, then of course Orochimaru can take all of Pain bodies.
It will be worse if he summons Jiraya .. With him having some knowldge on Pain's fighting style, and Orochimaru already has better summoning then Pain.