1. 是不是cover所有的险种，除了房产和车子，地震险和flood insurance等也包括在内不需要单独再买？
No, umbrealla insurance is ON TOP OF other insurance. Individual insurance plan (home, auto, earthquake etc) pays first, and if not enough, umbrealla pays. You have to purchase sufficient home owner and auto insurance before the insurance company will sell you umbrella.
2. 是不是cover所有的家庭成员，也包括住在家里的小孩子？
One thing keep in mind is that Umbrealla insurance is protecting you from being sued/claimed by others. It does not protect you from yourself (such as self-harming accidents caused by your own negligence). If you drive your car on driveway and hit your child, umbrella insurance does not pay because you cannot sue yourself.
Yes, it covers adult, children, even pet's liability to others. Liability = compensation you pay to others for wrongs you committed. Including your kids or dog injurying other people, injury guest suffered in your house. etc.
3. 怎么买？就自住房（新房子）的话，该买多少合适？
It depends on your sitiation, if your kids is a teenager driver, you are advised to purchase umbrealla. If you have a rental house, you are recommended to purchase. Otherwise, it is optional and it's up to you.
