It seems to me that the two forces struggling when the narrator bites back her tongue are Meimei vs. self. This meaning, the narrator is battling herself, her Meimei self. Her family called her that way because she was the youngest sister. It seems to me that is a battle against her childhood, her attempt to be or, at least, act as a grown up. Her mother is telling she to restrain her childish whim.
Many topics from "The Things They Carried" are still relevant today, the constant theme is the horrors of war, and how they affect ill-prepared men, both physically and mentally. Many of the items they carry are symbolic as well as practical, used as a reflection of their own battles, and serve as a bridge between their fantasy world and reality.
Ultimately, their psychological baggage becomes the hindrance that leads them to their death.
False. It should say anyone. Hope this helps.
