I agree with Jazzercise, and I would recommend you to ask someone in the area, but here are my thoughts:
When one is applying for the PR and the visitor visa expires, is necessary to request an extension for the visitor visa (if this person didn't apply for the OWP).
Well, the OWP includes the extensions. So if they don't approve the OWP, I believe they will give an extension because of the PR process. If they didn't approve the OWP and also didn't give you an extension (eTA), I would recommend applying for the visa extension ASAP because your PR application is being processing still. But I've never heard about OWP being refused here...
I believe it will be ok if you know you are eligible
Has anybody seen an OPW app. refused?