I am not a teacher.
Let's try renumbering the questions, shall we? If they're all 1. things could be a bit confusing.
All of your answers look OK to me, but for number 3. I would have given the other answer.
I believe that in AmE there is a preference for the simple past (please feel free to correct me everyone), but as for the sequence of events, the skirt was bought before being ripped or before I got angry about it, so the past perfect sounds more natural to me. Compare that with, 'My cat ripped my skirt! I was so mad, I just threw it away!'
So to answer your final question, 3. could support either tense.