1. If you get in, then you get in. High grades are a necessity but will not guarantee you a place alone. Case in point: me.
2. No. It's not as if you can buy your way in. The actual ratio is something like 3:1 or 2:1 state schools to private schools.
3. It's only 8 week terms with intense workload, people still do manage to fit in other activities.. but from those student Q&As I've seen, it's definitely a tight squeeze.
4. Come on, of course not.
5. I think it's about 30% international students?