the bolded statements are my answer
hello, hello deidara senpai
Why hello captainEO 
Well Itachi too knows water style jutsu and is a master in it you could imagine since he spent years with Kisame.
true itachi does have water but remember preta and the sheild are still their
You also forget Itachi has yata mirror which can block ANY attack
itachi wont be able to use it that long if hes resorting to susano because his body will be exhausted it could but for a limited time really and it would most likely be around the end of the fight and he would be exhausted enough aready
People seem to think that tsukuyomi has to last for 72 hours it doesn't. He can halve it or split it into three so instead of one 72 hour it could be three 24 hour ones or four 18 hour ones. so that's 4 tsukuyomi for the cost of one.
i really dont understand this post
Animal paths are useless because of Amaterasu and totsuka. tskuyomi lasts a second and no one can break you out of it
not at all useless pain/nagato has a lot of summons itachi cant spam that much if itachi tried that he will die
Solution to deva is genjutsu. Deva is the first Itachi should attack. Also chibaku tensei is almost self-sacrifice seeing as though all the other paths might die as a result. And if it comes to it I'm pretty sure Itachi can just use 3 yasaka magatamas to destroy chibaku tensei