@subtain,
You are most welcome. Let's just say i have seen a good number of applications, mindsets and CIC responses.
At times, there are genuinely weird outcomes, but in 90% cases, VO manner of executions go by book and are not really unpredictable.
So i won't say getting a SOWP has higher chances compared to trv. I think if you stick to a genuine situation and provide reasonable proof, you might very well get it.
Since she does not want to go there to work (or live with you for as long as you are there with the possible right to work), if i were in your situation, i would apply for a trv, explaining my situation in a brief cover letter. Her educational docs - showing the status of her current degree would help and might serve as a strong tie.
On the other hand considering your PR application was submitted in land (i assume this is the case), you basically have a right to get OWP irrespective of your job (skilled job) restriction does not apply after AOR of inland application, as far as i remember.
Bottom line, i don't think any of these has higher or lesser probability given your circumstances. But do attach your AOR with application.
And yes for a Person on a work permit with PR in process, a shorter visit's intent doesn't look very promising. You can very well apply for SOWP and say if questioned or opposed that the intent was to still come back to finish program.