I reas that it’s almost impossible to get vistor visa for one’s spouse outside of Canada. What are chance that my wife’s status as visitor will be restored?
When applying for restoration they ask for what period she’d like to stay, should we choose less than 6 moths or more, does it matter?
Regarding visitor visa for a spouse outside Canada is indeed harder to get, but not impossible.
Restoration of status: my guess is that it will very likely be approved especially if you explain how it happened that she is out of status, that it was not intentional.
The duration doesn't matter much honestly. Once her status is restored as a visitor and that you have an ongoing application for sponsorship and OWP, she will have her status valid here.
She should really not worry about being deported. Again, I don't recommend going that way, but having no legal status in Canada doesn't prevent her to get PR via spousal sponsorship. Not having a legal status in Canada is not a motive for refusal. There are several cases like that every year. I suggest you read a bit the inland spousal sponsorship thread (2016, 2017, 2018). You will see there are several cases that were processed and cases that are being processed.
Also, I recommend you to google "IP-8 CIC manual". Download the first pdf in the list. This is the manual from Immigration Canada regarding spouse and common-law partner in Canada class. It's full of very useful information. In that manual, you will find that in page 64 and similar info in other pages:
"The effect of the policy is
to exempt applicants from the requirement under R124(b)
to be in status and the requirements under A21(1) and R72(1)(e)(i)
to not be inadmissible due to a lack of status; however, all other requirements of the class apply and applicants will be processed based on guidelines in IP 2 and IP 8"