You should know that VIU does not rank in the top-20 Business schools in Canada.
1. For any course less than 2 years, the PGWP is issued for a duration equal to the length of the course. The MBA course is 20 months, so you could get a PGWP of 20 months duration.
2. You can have on-campus and off-campus accommodation. Its harder to get on-campus accommodation as its usually allocated based on academic merit.
To start with, assume that you'll have off-campus accommodation.
3. The Campus is located close to Nanaimo, on Vancouver Island. This island has some of the most scenic locations in Canada. A ferry ride from Mainland Vancouver across the Georgia Strait takes one hour forty minutes to reach. The point being that you need to account for the time and cost of such trips when you travel to the mainland.
Check this link for costs:
https://international.viu.ca/cost-calculator
Select MBA as the course, and off-campus accommodation. This shows a tuition fee of C$ 48, 858 (say 49,000) with basic monthly costs of C$1,441 (say 1,500). Note that the monthly expenses calculated only allocate C$100 as other expenses, which is too low a figure to include Internet, BC Hydro (Power), any entertainment/ recreation / travel costs, monthly cell phone bill. A more realistic figure would be at least C$250, but for the purposes of this calculation, you may continue with C$ 100.
All in all, for a course of 20 months duration, you will pay C$49,000 (tuition) and C$30,000 (lifestyle costs); totalling to approximately C$ 79,000.
Good luck.