his plan involving Sasuke is disgusting.
Yes, but not because it's not a clever plan, just because it is morally horrid.
Kill everyone, torture Sasuke, get Sasuke on the path to revenge, kill me, unlock MS, he takes my MS, he gets EMS, use KA to make him good...
You are listing all these as if they were all part of a single plan while they weren't. And you're missing various points about the plan itself, also.
Alright, why didn't realistically Itachi explain what was going on and explain why he killed the Uchiha, calmly and slowly and then take Sasuke with him and leave the village together? Then one day if Itachi dies, Sasuke gets the MS etc. etc. Why did he use this weirdo plan to use Sasuke?
Itachi is a great character because he isn't a walking mass of goodness like some seem to think. Among his desires there was the very selfish one to keep his clan's name clean, and he assumed that the same was true for Sasuke - that Sasuke would be prefer thinking Itachi as a mass murderer rather than knowing their clan for what they really were. A very big mistake he himself admitted after defeating Kabuto. Saying "I killed them and that's the just reason I had" was just no option for him, it would be like killing them twice.
Itachi of all people, knowing the history of the Uchiha and whatnot, should've known not to put Sasuke on a path of revenge.
Itachi thought he could control the situation. He admitted even this mistake, once to Naruto and once again to Sasuke itself. He basically tried over and over again to manipulate Sasuke.
Essentially you're missing various traits of Itachi's personality. He is manipulative, coercitive, and thinks he can keep everything in control. Which is really believable for someone who is a triple-agent spy and an acclaimed genius estranged by his own famous lineage.
Also, what would he do if Danzo killed Sasuke? Go kill Danzo? Like that'll bring Sasuke back right,.?
Agreement with Danzo and the others: I won't say that you ordered the massacre and nobody will harm Sasuke. WOrked pretty well, too, considering nobody tried to except Danzo via Sai once, when Sasuke gave them the excuse that he turned a criminal. Danzo only ordered explicitly his elimination after Itachi's death was confirmed. And before Hiruzen died it wasn't even in question that someone could touch Sasuke...and after Hiruzen died, Itachi paid a visit to Konoha and then again for two long years nobody dared suggest to harm Sasuke. All of this is pretty consistent with the fact that otherwise Itachi could reveal the secret of the Uchiha massacre and that the "peaceful" Konoha was basically built upon a bloodshed.
And what if Sasuke killed himself..? What would he do then?
That had nothing to do with Itachi himself. Sasuke was born out of a family of ninja and wanted to keep the tradition. He was bound to end in dangerous situations since youth anyway.
Second, Sasuke killing Itachi would make him unlock the MS how..?
It wouldn't. Itachi's plan didn't include Sasuke acquiring the Magenkyo. You confuse Itachi's main plan with his backup plans. In case Tobi tried to speak with Sasuke, Itachi got a backup plan in sealing his own Amaterasu in Sasuke's eye, setting it up to react to Tobi and kill him. In case it failed, Itachi already told Sasuke that "Madara" (Tobi) is untrustworthy. In case Sasuke trusts "Madara" anyway, Itachi left his Kotoamatsukami in Naruto's body to literally brainwash Sasuke once again and fill it with an unexplicable desire to protect Konoha.
These weren't the core part of the plan just some back up emergency routes. It is telling that most of those included manipulating Sasuke in an even deeper way, by killing a possibile truth-teller or incepting an idea in Sasuke's own mind forcibly.
Itachi endangered Naruto for gods sakes by telling Sasuke to kill his best friend! He injured to a huge extent Kakashi - how would he have known Tsunade would save him? What if the Tsukuyomi he used on child Sasuke killed him? Also, Sasuke should've been dead had Tsunade not been Hokage.
That is once again where Itachi's arrogance comes into play. He was already in the act of being a very violent psychopath and kept with the act,which served to keep his agreement with Danzo, mantain his role as a spy into Akatsuki and keep Sasuke into his delusion. He did all sorts of things a sadistic maniac would do, including scarring Sasuke mentally and physically and hit him (and Kakashi) with dangerous, albeit non-lethal, jutsu. He knew he was taking gambles. He was convinced that Sasuke wouldn't kill a friend and that the Konoha villagers would cure him from the Tsukuyomi somehow and he was correct on both instances. His written path for Sasuke stopped working sometime after that (more on it down)
What if it was Danzo chosen as the next Hokage..? How about Kakashi..? Shikamaru..? Shikaku..? Any of them would've killed Sasuke when they had thr chance for being a missing - nin.
See point 2. Nobody would touch Sasuke until Itachi and Hiruzen are both dead. And by then, Sasuke would already be back on Konoha as a hero.
Speaking of missing nin, itachi is smart and should no, even if Itachi is killed that Konoha won't accept him back.
How so? Sasuke left the village only due to Orochimaru's influence, which then again was after Sasuke only because he tried to take Itachi's body and Itachi owned him. Itachi knew he could erase Orochimaru at any point - which is exactly what he did when he unleashed the Susanoo exactly in order to make Orochimaru appear from within Sasuke. Sasuke defecting to the Sound Village was the only thing that didn't go according to Itachi's plan and he thought he had the means to correct that. Once again he was arrogant because he underestimated Orochimaru and his Curse-Seal method of revival.
Sasuke would (in Itachi's mind) then be the one shinobi that in is youth killed Orochimaru and Itachi, two dangerous missing nins. And he'd be left with one desire: to rebuild the Uchiha clan, the proud clan he and Itachi once belonged to who was among Konoha's founders. What would then Sasuke try to do? Return to the village to rebuild the clan. Will they shun such a powerful and heroic shinobi? Most likely not.
Adding on, fugaku and mikoto accepted Itachi's resolve, so why didn't itachi try and you know...talk?
Diplomatic attempts were tried over and over, as it is explicitly stated. Keep in mind that the Uchiha clan was shrinked down from one of the two major forces of Konohagakure to a handful shinobis who were already bound to their role by birth - they weren't in the right mood to stop a coup d'etat once they had it set up.