It is quite obvious that you only have your wife with you to accompany you in canada since the addl family information should provide info that you dont have any children AND that you provided an info that only 2 are on your family in the first part of the form, so I guess its probably OK to leave it blank. The only ones whom they sent back are the ones that have information that are kinda impt e.g. Other citizenship held, dates, signatures, omitted a form, credit card payment errors etc..
But if you are not entirely confident you can opt to resend the application now and see how that go so you can save yourself 2-3 months of wait. Try searching the forums where someone resend another application within a week of his initial application to CIO, i remember reading a thread on that somewhere.
God Bless!
BM