Hi good morning,
COncerning finger prints and RCMP you should take a look on this link : http://www.cic.gc.ca/english/helpcentre/answer.asp?q=857&t=25
It mentionned : If you have lived in Canada for more than 6 months after the age of 18, a background check may be automatically conducted with the Royal Canadian Mounted Police (RCMP). If your name has a 50% or more match in their data base, the RCMP may request fingerprints in order to confirm your identity. So mi I think I would be proactive and do it before they request it.
Concerning the baby, me I would send another form Additional Family Information form IMM 5406 by email http://www.cic.gc.ca/english/pdf/kits/forms/IMM5406E.pdf and add the information with my new kid. Apparently it is not a good idea to send more proofs of Relationship like pictures and trips details. So in your email just ask them if they need the original of the form or other documents and if yes to advise you. That is what I would do.
So I hope this help !
Congrats for the new baby