1) you can't start sponsor application until you are in Canada , so it would be when you come back to Canada
2) you sponsor him/her for PR , once baby is PR , baby can stay in Canada , you sign for financial sponsoring for 10 years ( double check this one , but doesn't really matter , you have to provide for your child anyway )
3)once PR yes , the tricky part is you have to apply for TRV for baby , which may or mayn't get approved ,so you risk separation from family until PR for baby is completed if you can't TRV
4) 5) baby will get citizenship with you , doesn't matter if baby gets PR late .
try to get your wife to give birth in Canada, so you avoid all this if you can