Theoretically, Animal Path SHOULD be able to summon Gedo Mazo, which would be a big problem for Itachi.
Preta Path would not be much of a problem once Itachi realizes that it can absorb ninjutsu. He would probably realize after a few techniques that using genjutsu would work much better.
Itachi cannot just spam Mangekyo techniques, so doing possibly THREE of them, then having to worry about Gedo Mazo would be a problem.
Konan hasn't shown me any techniques that would be useful against Itachi. Sure, she did good damage to Tobi, but that was with preparation to kill him.
I say at the worst, Itachi dies with just Animal Path standing. At the best, he takes out three of them and dies in the struggle.