Hello there, I believe its preferrable to get a new passport for your wife with same details as yours. Also once you'll be blessed with kids, all u need to do get his/her birth certificate, passport and fill up another form by adding the additional detials of your kid (s) and send to immigeration in islamabad by giving reference to your file number. Also visit
www.cic.ca for further details. In the mean while you change address or names can enter online too on same site.