this has to split into 1 vs 1s or it will be a cluster****.
edo nagato would hold off tobi because he has nothing that can get close to nagato without edo jins. he may get close but nagato has gale palm, preta, and ST to push him away. or konan summon to blow him up with a paper clone when he tries sucking himself up to avoid CT. remember konan was alive when nagato was first summoned and shed defs fight for him. cerberus cant die. nagato can fly or levitate. moreover, e bijuudama gets absorbed. i suppose tobi + edo jins will eventually enable nagato to be held down so tobi can tear his soul out. if not then nagato seals tobi with gedo mazo soul dragon. i dont think tobi will use that since hes a living being and needs to stay healthy for the juubi subjugation.
edo itachi and naruto will have to be handled by edo madara. hashirama and sasuke the weak links fight each other. madara manages to restrain itachi inside a mokuton prison or in his PS hand. naruto attempts to free him but preta tanks all, and eventually madara drags down two meteors. naruto wastes his imperfect BM on stopping it and is murdered.
if necessary madara and hashi will go help tobi vs nagato.
Itachi has the brains to figure out away to beat them
all the intelligence in the world wont save you from overwhelming power. tobi vs itachi is like fukin shikaku vs pain.