I will talk about question number one. In my opinion, kids do not need to learn second language because the important thing for kids is how to talk, it does not matter what the language is.
I remember when my son was two or three years old, my husband and I taught him Arabic language and sometimes English language too, but it was not effective because he studied in public school where either Arabic or English are never used. His friends, also, only used Indonesia and Jawa languages. Since we wanted him to learn other languages, my husband and I decided to only use one language.
Another example is when we lived in East Jawa province. Of course, we were always using Jawa Language. On the other hand, my husband did not use Jawa language well because he is a maduress, people from a different island and a different language too. My husband could only chat with my son by Indonesian language. Indeed, I thought that I wanted my son talking with his mother language since in my mother language we have diversity levels. To illustrate, chatting with elders is a different style then if we chat with those from a similar generation. In addition, in my culture giving good respect for the older generation through language is very important. Obviously, when my son entrers into school, he could speak Indonesian naturally. In short, my husband agreed to follow my opinion.
Second Language Class HELP 2006