Well I don't see how Itachi could have killed Tobi, the guy has already proven himself as smarter then Itachi, and Itachi was his apprentice. Only reason Tobi didn't attack Konoha was because Itachi made a deal with him, the deal being that Itachi would help Tobi get his revenge on the Uchiha clan (massacre) and that he would join Akatsuki and help him with his plans if he left Konoha alone. But Tobi was one step ahead the whole time, seing through Itachi's real motives and countering with his own secrete plan to get sasuke when the time came for the fight between 'brothers'.
As for Itachi's lack of respect for Minato, well, I don't recall that scene, I thought he said that 'even the fourth had help from his friends' or something like that. But if he did call him Minato, then I don't know, I think to fully grasp the situation we would have to hear him talk about Tobirama, Tsunade, and Hashirama, Hiruzen was the reigning Kage when Itachi was a konoha shinobi and promised to protect sasuke from Danzo so he would obviously show respect for him.
But if Itachi were to show respect for all the other Hokages too and not Minato, then only then can we really say that he was disrespecting Minato specifically.
If he doesn't show respect for those other three as well, then he is just a rebelious child that needs a good spanking and should learn respect for his elders.
Although all the other three are senju's, being that Itachi is an Uchiha, I wouldn't be surprised if he didn't use a respectful honorific for them, after all, it was Hashirama and Tobirama that started this 'opress' the uchiha clan regime that eventually lead to the Uchiha rebellion which resulted in Itachi betray his own family.
I do however believe that Itachi is an evil psycho or at the very least, a selfish and misguided individual who believes he is actually selfless, or maybe he was just a loyal 'tool' or 'puppet' that was manipulated by the Konoha elders (Hiruzen included).
1) Itachi was either selfish or ignorant for expecting the Uchiha clan to just sit back and leave things the way they were. Clearly this was no longer what they assigned for, Konoha was supposed to be a partnership between the senju and the Uchiha, but like Madara predicted would happen, the system ended up promoting the senju clan and its supporters and opressing the Uchiha. Just look at the Hokages, the first and second were senjus, the third a student of the senju brothers, the fourth a student of a student of the third, who is also a student of the senju brothers, and the fifth once again a senju. Itachi and Shisui both had the potential, strength, and mentally to make it but they were used and tossed aside and even manipulated by the Konoha hierachy (Shisui and Itachi's ninja ways were a blend between Hiruxen and Danzo's ways if analyzed carefully, plus Itachi and Shisui had strong ties to both those characters.) Any point here is that the Uchiha had every right to fight against their opression, otherwise nothing would have changed, imagine if women never opposed gender discrimination, Jews never opposed discrimination in germany, or african americans never opposed discrimination against them in the US, things would never have changed, someone had to stand up and say this is bull before things changed, Itachi was selfish and self centred for expecting less from the clan just because he was too scared of war, war is sometimes a neccessity, he was supposed to help his family, how can you choose corrupt strangers over your own family? Your own mother and father, who fed you, raised you, gabe you the best shinobi education and trusted and loved you, especially his mother.
2) His relations to Sasuke are more for himself and his own goals then Sasuke. He had been manipulating Sasuke all this time and lied so much just to get Sasuke to be a konoha puppet like him. You can't make someone live a fake life if you trully wish the best for them, Sasuke had a right to know what happened to his family and had a right to make his own choice, the guy tried so hard to rob sasuke of that choice and even tried to use the despicable Koto amatsu kami to literally turn Sasuke into a puppet for konoha just like he was. He had no right to impose his will on sasuke like that, sasuke doesn't have to live like him, if he really cared about him he would have let him live his own life and make his own choices, Sasuke has his own goals and dreams, to restore his clan and attain justice for his family but Itachi tried to rob him of that and make him protect the very people responsible for his clan's suffering and ultimate destruction.
Either this is all subject to interpretation but I don't think in any kind of Interpretation one can justify killing their own family, especially for their opressors.
Itachi is the worst kind of scum, a true traitor who deserves far worse them what he has gotten, if you can strike your own family like that. The only thing worthy of respect is his power, but not the person himself.
And he should show a little respect to Minato, without Minato, he and the rest of Konoha would have been destroyed by Tobi and Kyubi, unless he has a history with Minato that we don't know about, he might possibly have one, Kushina and Mikoto were good buddies, so Itachi might have met Minato through that relationship or something.