That is a lot. Let me answer a few of them.
1, 2. Mrs. Schachter did scream fire because she sensed that the stories she heard were true. She was past the point of denial, unlike others on the cattle train. She was right to sense this danger, as this foreshadowed the lot of many people. The people would be the "wood" or "coal" of the furnaces.
"Fire! I see a fire! I see a fire!"
There was a moment of panic. Who had screamed? It was Mrs. Schächter. Standing in the middle of the car, in the faint light fil- tering through the windows, she looked like a withered tree in a field of wheat. She was howling, pointing through the window:
"Look! Look at this fire! This terrible fire! Have mercy on me!"
3. Men and women were separated, and this was a defining moment for Elie because he would never see his mother again. Their family was rent asunder in one moment.
4. They lied about their ages because Elie's father wanted to seem young and Elie wanted to seem older. The SS would probably kill people who were too old because they knew that they would not make it. And they would also probably kill kids, because they could not do work and required food. So, their decision to lie about their ages was to survive.