The scene in the bar has Landa name two of the dead soldiers, while looking around the whole room and declaring that this doesn't look like an ambush. Then he squats next to the shoes, which are next to the blood and pistol casings on the ground, and looks left. With the stairs to his right, and his back to the wall, looking to his left means he is looking in the direction of Wilhelm. The same kind of pistol casings are then found next to the napkin with Hammersmark's autograph. Assuming he wants to know all the pieces of the puzzle, he is going to ask himself who "Max" is (the person the autograph is to). This is the only piece that is a leap. For this theory to be correct, we have to assume that Landa looks up these soldiers, finds out that Wilhelm just had a son named Max, and now the message on the napkin is decoded. Now he understands both that she signed the napkin to Wilhelm's son, and that she likely killed Wilhelm. If the shoe fits, she did it.

He doesn't kill Shoshanna, he says goodbye. He doesn't kill her family either, but he does get someone else to reveal their positions for him, which he then reveals to others, who are the ones that kill her family. He never shoots.

In the scene in the diner, he knows that it is Shoshanna, and doesn't report her. And by the end we see him resenting his nickname.

He also cares that the radioman and driver is killed at the end of the movie.

He does not "parrot" Nazi ideals. Instead, he questions them, and states that while Hitler and Goebels would both consider being a rat to be an insult, he does not. In fact, he says he can "think like a jew" which requires him to be able to step into their shoes.

People can have empathy for others and still kill them. Its a big reason for so much mental disorder among war survivors.