Funds available for my stay (CAD)

It might be better to indicate the total amount available, as you'll also list those with whom you'll travel. While you will be travelling together, you'll file three, separate forms (IMM 5257), one for each of the adults, and one on behalf of your minor child (which you will sign). However, both you and your wife will also fill in the the Family Information form (IMM 5645); it makes it clear that you are a family, entering Canada and that there are shared expenses (e.g., accommodation). You can submit all family member applications in the same envelope with one payment receipt for the total fee for all of your applications.