Come on, that's not the same as a DarkHallow. There is a difference in killing people for power, and casualties if war. His targets were the evil Red Court vampires, the innocents that died as a result weren't targets, but other victims of the Red's who'd been infected without permission.
I agree with your first point.
I think the innocence being talked about were the people infected, but not turned who died. Only the younger once's survived I believe.
No, he's right, I meant the vampires. And from their perspective, they're innocent. They have to feed in order to survive, they see humans as herd animals, so they have no qualms about slaughtering them to feed themselves.
Yes, they still have to be killed on basic principle, it's an "us and them" kind of situation. Wiping out an entire species was a concious choice for Harry, fueled by need and much anger. He was quite unhinged in Changes, and DarkHallow was a step away. That's still a moot point though, I can't see how he could manage DarkHallow in such little time, he didn't prepare the way as the Kemmlerites did in Dead Beat, no collective fear, necromantic energy to protect him, and with a broken back. At that point the only viable options were the Coin or Mab.