Let me try to answer some of your questions. Though I do not think I will be of great help to you as I am out of school long time ago.
1. First, kids can go to school at the age 7 (that usual) But some might go at the age of 6 if the parents think that the child is ready for school. Children study 10 years at school. There are public schools - there children study for free, and private schools where they (or it's better to say their parents) have to pay for the education. There are different types of private schools and mostly they differ in their specialization ( I mean the major subjects, such as English, Math or etc.)
2. I can't help you with that as the program has changed and I do not know anything about the new program.
5. Well, I will move to 5. The students can study English, German and French. These are the most popular. In private schoos they can also study Latin. On rare occasions it might be Spanish but it is very rare!
Hope I was able to help you a little bit with that!