Canada

Yes you can and after getting PR there, you can continue your studies at domestic rate.

Approximately 15-30 days.

You must at least bring 6.5 and 6 in each section for good chances. But, you should try to get 7 or above in overall.

You need to score 60% in Bachelors degree.

Why not? If you meet the requirements you can. See that you have good academic grades and take the IELTS or TOEFL. You must contact the college for admissions in MS as your visa will be valid only for four years initially. You can also look for integrated options or pathway programs.

Hi, you must clear the licensing examination first. Please check the Dental Council Canada website for more details. Here is the website
https://www.ndeb-bned.ca/en

You can apply, check the entry requirements before applying. The top universities will be very difficult as they have higher requirements and candidates with previous backlogs are not preferred. You must also take the IELTS or TOEFL. In case you take IELTS a score of 6.5 with no section less than 6 will be required. If you take TOEFL you must score above 90. Please visit the university websites for more information.

Either of the two is good. Canada has more reputed universities compared to New Zealand. You must also consider other factors such as cost, university requirements, your profile, climate, etc. Both the countries are popular and have post study work permit options including PR schemes, which attracts a lot of international students.

Australia is slightly easier but only if you have the qualifications listed as per the SOL, you must also have a job and have the skills. Having said that, obtaining PR is slightly tough in Canada as there is no separate pool for international candidates and work permit schemes follow provincial rules and nomination, so it becomes tough. Irrespective of both the countries you must have the necessary skills and qualifications.