It's called a field or an oval.
Australian Rules Football
There is no specified size requirement for an Australian Football field. Australian Rules was originally created to keep cricket players fit in the off season and cricket fields do not have size requirements hence why Australian Rules fields do not have size requirements.
Yes. The endzone is included in the distance of a field goal.
The length of a track around a football field is exactly 400 meters.
100 yards, on a professional sized football field.