Canada

You need to do minimum one year course. International students will not be admitted for short duration courses. Even if they admit, you will not be eligible for PR. New Zealand: You can take up level 7 one year Diploma. After one year study visa you will be given one year work search visa. Once you get a job, you will get two year work permit, the moment you get your work permit you can apply for PR. In other words you are likely to get PR in two years and six months. Canada: If you do one year study, you will be allowed one more year post study work visa. Once you get a job, you can get work permit and apply for PR.
England: You are not allowed to do apply for 6 months course. You can go for one year Masters programme. On completion if get a job on your profile, then you will be eligible apply for tier 2 visa for five years. If you don't get the job you might have to return to India. Australia only if you do two year programme you are eligible to apply for PR.