I think if you applied inland, your spouse can take courses that will take 6 months or less to get a certificate. If it takes longer than 6 months to get a ceritficate or degree, she will have to get a study permit.
Honestly, I think it's best for her to apply outland, then apply for a visitor visa to Canada, and just remain in Canada until she gets her PR. She can always try for an extension should she not get PR before the visitor visa expires. By going outland, at least she will get her PR much more quickly than inland, then she won't have to pay international student tuition fees.
As for the OWP program, honestly I think it's better to get her PR in 6-8 months without working, than working in 4 months, but forced to remain in Canada for over 2 years and paying international rates on tuition.