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Starting from the 15th of March 2016 you'll need an eTA to transit or stay in Canada. This is true for nationals travelling on New Zealand, as well as Taiwanese passports. Quoting from the Canadian CIC website, below is the information for New Zealand citizens:
and for Taiwanese citizens:
You'll therefore need to secure an eTA to be able to layover in Vancouver airport, regardless if you are wishing to meet your friend or not. The cost of the application is 7 $CAD.
With the eTA you should be able to leave the transit area of the airport and meet them. If you are looking for inspiration on where to meet your friend, note that the Vancouver airport website has a dedicate page on meeting places.