1. The active may've been crass and tactless or your daughter may be sensitive. Hard to tell. The active may've been really nice but her curiosity was loud and in the wrong venue. Who knows.
2. Life happens. Your daughter will be okay. ETA: libra's advice sounds good, too.
3. I don't know what you mean by "she continued with 'bra' while they were in line for food." What does that mean?
4. Did your daughter intend for you to bring this here when she told you? I hope not because sometimes we want to talk to a friend or parent without it going further than that, let alone a message board. Just make sure you don't get too involved.