Easy to get:Student Visa or Visitor Visa?

[Taiwan-Canada]

Hi,

I'm going to get married in Taiwan in March.
I will support her here in Canada while she is waiting for her PR.

To increase her chance to stay as longer as possible while she is waiting,

1.Should she get from Taiwan a ...
-Student visa and go to any schools(ex.:advanced english class)
and ask for extension every 6 months

or

-Visitor visa and ask for extension every 6 months?

2.Does she have to USA to ask extension in both case?

Thanks
Andrew