1. I prefer English.
2. No difference between 回郵信封attn比小朋友, 定家長, only if the address is correct.
3. I 會填落去個人簡介到.
4. If the school has more than one day for interview, I prefer 交表日期會選擇尾那一個時段. Because the interview might be arranged on the last date so taht I could get some more information from those who attended the interview before my children. Right!!!
In fact, all the above are not important. The most important is the performance of your children during the interview.