Please, someone, correct if I am wrong, but there is still much theological and philosophical debate on whether lying is truly an intrinsic evil (torture for anti-terrorist purposes is also still being debated). Please take a look at these links for more info regarding these matters.
As for killing in self-defense, here is what the Catechism has to say:
2263 The legitimate defense of persons and societies is not an exception to the prohibition against the murder of the innocent that constitutes intentional killing. "The act of self-defense can have a double effect: the preservation of one’s own life; and the killing of the aggressor. . . . The one is intended, the other is not."
Here is a guide to the “double-effect principle:”
As for the principle, “doing evil for a greater good,” you do not have to do much research into the Catholic faith to know that that is one of the most evil and vile beliefs this world has ever seen. For example, if killing one man saves a thousand, then why not kill a thousand to save a million or a million to save…whatever a million times a million is. Even if this type of evil were committed by a single person, it is still a scandalous form of evil. Many people would see how convenient it is to commit evil for some greater cause and, eventually, everyone would start doing evil. In the end, only good brings good and only more evil is created as a result of evil.
Indeed, there are times when morality may seem “gray” but it is not. As there is God and the devil, there is only black and white. Its just that what constitutes “black and white” is very complex. You will find that out if you read into these links well enough. I hope this helps.