Ah yes the zombie bros. Yeah well I don't think Kakuzu counts and Hidan was such a joke of a character but if you wish to label those two as "evil" fine with me. I'm not going to argue it, unless you really really want me to
Yes. The entire point of the 'shinobi' alliance is for them to put their previous and relatively petty squabbles aside and join forces to stop Madara because if he wins, everything ends. Not forget no but put it aside for now, the Uchiha and the Senju did it when they joined forces to create Konoha, that is pretty much what this flashback was about.
Yeah you can put that aside for now too, pretty much the same way the Leaf didn't do anything against the Sand for allowing themselves to be manipulated into attacking them. The only murder you can legitimately argue that Sasuke could really be held accountable for is Danzo, who had to be taken care of one way or another. Deidara, Orochimaru and Itachi were all S ranked criminals anyway. As has been mentioned before if he had returned to Konoha after fighting Itachi he would have been welcomed with open arms, plus as was also mentioned all the other people Sasuke has faced in battle were not killed, for example. Karin is not a character, I have no idea what she is or why she exists. The only use she seems to have is her chakra sensing abilities and the only other significant things she has done is letting Sasuke bite and stab her. Funny that both she and Orochimaru mentioned Sasuke stabbing them.
Yes the flip side, this was going to happen anyway. There is the Naruto-Gaara parallel, not to mention Naruto's single minded determination to "save" Sasuke to prove his way of the ninja. Naruto's many speeches about how he is going to change the ninja world and what it means to be a shinobi once he becomes Hokage, pretty much since Haku died. We knew this was going to happen as soon as we found out the truth about Itachi. I honestly expected some moving speech by the revived Itachi to be Sasuke's turning point but this works too and it is far more plausible than Naruto winning him over with his power of friendship BS. Seriously this isn't Mortal Kombat, you don't friendship someone after you beat them.
Might happen but you seem to be ignoring the fact that Sasuke's help, and through him Orochimaru and the freaking undead Hokages, will be the deciding factor in this battle. Something I think we all knew from the beginning of this war. That in itself would be enough for the shinobi to grant Sasuke amnesty, something Naruto has been campaigning for and saving the world kinda does trump everything else.