奥様もPR保持者、お子様はカナダ生まれではないがPR保持者ですか?
Determine your eligibility – Citizenship
http://www.cic.gc.ca/english/citizenship/become-eligibility.asp
の
Ageの欄に
To apply for citizenship for a child under 18:
you must be the child’s parent, adoptive parent or legal guardian,
the child must be a permanent resident, and
one parent must be a Canadian citizen or apply to become a citizen at the same time (this also applies to adoptive parents).
とありますので、お子様がPR保持者であれば、
お父様であるトピ主さんの市民権申請と同時にお子様の分の申請も行えばよいのでは?
奥様の市民権は、別途申請が必要だと思いますが。