Well, Itachi should be able to see through Nidaime Mizukage's illusion because of his Sharingan - i'm not completely convinced it's enough to locate Mū, however. He supposedly has neither chakra nor form, so you wouldn't expect there to be anything regular ocular powers can use to identify his position. Another issue is whether or not Mū can attack whilst maintaining the technique which earned him the 'Non-Person' nickname. We haven't actually seen him do so, despite being in a situation where such a combination would've come in handy. Since plot induced stupidity is the only other explanation, i'll assume, for now, that it's beyond his powers.
Itachi'll be able to direct Minato away from danger and towards the clam, which can be destroyed by Kuchiyose: Yatai Kuzushi or simply teleported to one of the various seals Yondaime has placed in Konoha. The same goes for Jōki Bōi. It's fast, but it isn't faster than Konoha's Yellow Flash. If he manages to lay a hand on it, a seal can be placed (so that it can be struck with a redirected Jinton or the like) or the clone can be transported away. A predominantly Yin Release user like the Nidaime is unlikely to be stopped by Genjutsu, particularly if he's aware that Itachi specializes in that art. He, however, has no real answer to Amaterasu, and that is where his night probably ends.
Now, Mū will need to be extremely cautious. Though Jinton will prove to be extremely useful, it isn't something he can spam - and he simply can't afford to be without his trump card when the boss summons and Susano'o come into play. He'd also need to look out for Minato's Jikūkan Kekkai, which could potentially redirect the blast onto Mū (Yondaime could even have Itachi throw [with Susano'o] multiple projectiles to reach the Tsuchikage if the latter chooses to fly out of regular throwing range. Frogs could also allow him to move closer to his target). Splitting wouldn't prove useful either as this weakens him to the degree where his Dust Release his unusable.
Amaterasu, again, is likely going to finish off Mū. Jinton would completely erase Itachi and his Susano'o from existence, but it isn't quicker than Amaterasu, and that's the problem. It seems the Tsuchikage needs to somewhat steady himself in order to charge the technique as well, and this is a further handicap on his powers. Although the two Nidaime's would fight gamely, I don't think they'd have enough in the tank to take the win.
