Thor hit him yes, there is no proof it killed him. For Scarlet Witch, I assume you mean the bomb. That was not a result of her acting recklessly. If she hadn't acted the bomb would have killed her, Captain America and an unknown number of civilians. She merely lost control of her power while trying to get rid of it.
I haven't seen the Hulk versus Abomination fight in years, so I can't really comment right now. But seeing as I've already admitted several members of The Avengers could be considered guilty of depraved-heart murder or out-and-out murder. Your claim that I'm specifically targeting Superman or acting in a bias manner honestly has no basis in reality.