You didn't need to inform CIC, so you did the right thing. You would have only needed to inform them if she actually delivered baby before PR was approved. Even if CIC/CBSA "noticed" she was pregnant upon landing, they wouldn't have done anything anyways since it's not an issue.
As mentioned above your daughter can sponsor her partner (father of child) ONLY once they are officially married or common-law (having lived together 12 continuous months at same address)
Your daughter can sponsor her child for PR, but there are some difficulties here.
As a PR, she must be living in Canada to submit the PR app, and during it's processing (up to around 1 year). During this time she would only be able to leave Canada for short/temporary vacations.
Peru citizens require a TRV to come to Canada, so both her child and partner would need to be approved for TRV in order to come to Canada during the sponsorship process. If child's TRV is refused, can also try a TRP (on H&C grounds).
If TRV/TRP are refused, then your daughter would need to return to Canada to sponsor child, but child would need to stay in Peru. Obviously this would be a very difficult situation, so you need to really hope TRV or TRP is approved for child to come to Canada as visitor with your daughter during the process.