As people have pointed out, Itachi wins. Alot of the "evidence" you provided in your OP is speculative or wrong/misleading. Bee couldn't beat either of them, and certainly not Itachi.
Let's also remember, alot of what Itachi supporters are saying works on the assumption that both fighters are equally intelligent, etc. In reality, whether you like it or not, Itachi is portrayed as being so analytical and farsighted, it borders on psychic. Itachi can usually predict how people will react, often how circumstances will play out, years in advance. Hidden something in a blind spot? Itachi can hit it anyway, even though it makes no sense. Kabuto has numbed your senses? It doesn't matter, Itachi knows what you're planning to do before you do it. Itachi was able to stage an elaborate fight, where he was just good enough to make Sasuke think he was fighting him to the death, but in reality was not trying.
There's a good reason Kishi got Itachi out of the Killer Bee/Naruto fight as fast as possible... because it would be impossible for Itachi and Nagato to lose against Bee and Naruto. I also find it strange that Bee advocates invoke a fight in which Itachi barely got warmed up before switching sides, and was unable to utilise his usual genius (because he was being controlled by Kabuto). If anything, that fight should make us very confident that he would take Bee, as without even using most of his abilities, he's still got no difficulty fighting off B/Naruto, while Nagato stands around for most of that portion of the fight.
Bee has no answer to Ameratsu. Bee has no answer to Totsuka. Bee has no answer to the Yata Mirror. And, as far as we can tell, he has no answer to Itachi's Genjutsu, which can take him out in 1 second if he makes eye contact. He has no answer to Izanami either. Heck, if we're taking Itachi at the peak of his power, he's got Shi Sui's eye too, which Bee also has no answer to. And this is discounting the fact that in every way, Itachi is portrayed as a mega genius at fighting, while Bee is portrayed as somewhere between a clown and "very talented" (good, but not near Itachi levels).
Bee looked good against a weaker Sasuke... but Sasuke has gotten ALOT stronger since then, while Bee has not. It's closer than Itachi, but he should still go down pretty clearly.