1, No, it just means your application is done, no one know when its been mailed unless you call the call centre, my friend application did not show close even after she got the certificate for like 6 days.
2, 1 day after they mail it,or more no one knows tbh all depended on Canada post at that point and you obviously don't know when they mail it so basically just wait
3, Yes, as long as she meets all the requirements
4,
https://www.canada.ca/en/immigratio...s/travel-documents-references-guarantors.html that will answer your question