1. By law if your family composition changes, i.e. after your baby is born you have to inform IRCC. You do not have to inform IRCC now. But until you become a PR, i.e. a landed PR and any time your family composition changes, it has to be inform to IRCC. Informing now is of no use, only after the baby is born that you have to inform.
2. YEs, then you can sponsor your child under family class sponsorship and util the application is approved, you can get a visitor's visa and then a visitor's record. If your baby is born in Canada, the baby will be a citizen by birth.
3. No, see 1. You will still have to inform IRCC even if your baby is non-accompanying and submit the baby's passport and medicals. All family members have to be admissible for criminality, medicals and security, whether accompanying to not. At this stage it does not make sense to have your baby as non-accompanying, and when you add your baby, your file will be processed with the baby and all family members will be issued a COPR together.
This helps and thanks for that. Will surely keep you posted.