There's no legal requirement to change her name, ever. If you want to do it for traditional purposes, you can change it at any point, but to avoid delays you should change it before or after. Whatever is on her passport is what will be on the COPR and PR Card. The COPR can not change names once issued, but you can apply for a reissue of the PR card (though I think the wait is pretty long for a new PR card).