回复：关于孩子的生日party, 有几个问题请教：

1) Just reminder them again, for a few kids your son think they will come, you can direct call the parents to make sure.

Next time, you should ask a few your personal friends to come, so you know at least some will show up for sure.

2) You should provide food for parents too, but you should ask the party host first if you are allowed to bring in any food/drink.

3) Yes, normally 10%-15% depend on the service.