Orochimaru doesn't have Itachi's Sharingan, that right there proves you wrong. Itachi > Orochimaru, that's canon.
That doesn't prove anything other than you're a troll. Try again.
There is no plot hole. This was cleared up when we learned Itachi was a double agent. Kisame even questioned why he of all people needed to run from Jiraiya. He was merely playing Kisame for a fool and can take down Jiraiya with the same difficultly he took down Orochimaru. Whether people want to believe it or not is up to them, but it's pretty clear at this point.
Kisame was hesitant to go after Naruto and said that he didn't even think Itachi would be a match for Jiraiya.
THAT was Itachi's out if he really wanted to lie. He could had said "You're right, Kisame. The situation is too dangerous for us."
But no, he didn't. Itachi insisted that he's Jiraiya's equal and continued after Naruto despite Kisame's hesitations.
So no, Itachi wasn't lying.
Kisame also questioned why Itachi needed to leave because he's supposedly in the same league as Jiraiya.
It's a good thing they left though, Itachi would had really put up less of a fight than those 3 Peins did.
Giant sword could be a reason in braking free from those snakes? No?
Defeating or stealing body isnt possible due to genjutsu alone.
Breaking free from those giant snakes? How? He was stuck to Sasuke's neck.
What are you trying to reference here?