That's simple, you will just need to submit fee for renewal of visit visa and another application form along with the sponsorship file and it will be renewed. In case if you do not apply for renewal of visit visa, she will still be legal in Canada while her Permanent Residence Application is in process . . . . though her visit visa has expired.
Not sure about OWP, but they will always insist on Permanent Resident Visa.
It's more difficult to get a TRV even before sponsorship approval . . . If she gets the visit visa, just apply under with in Canada option, its simple . . .
The only thing that you might need to consider is her medical insurance, but if you have your wife with you, she must worth more than medical expenses and of course waiting around 18 months.
I will say again, keep preparing your sponsorship file, while applying TRV, it's really hard.
Just a tip : for TRV you must prove that she will leave the country after expiry of her visa . . . .