I forgot to include the following sentences.

Question

3)What kind/type of school do you go to? I go to a private school.
4) How do you spend your free time?
What do you do in your free time?
5) How far do you walk to school? How many kilometers do you walk to school? I walk 3 kilometers to school.
6) When do you arrive at school? Do you arrive there on time?
7) How much water do you have in the house? What do you like to do (doing) at weekends?
8) They don't eat enough vegetables. How much green food do they eat? How many vegetables do they eat?

Answer 1

All are fine, except in #7 -- not "doing."

Answer 2

Also for #7, say "on weekends" instead of "at weekends".