My wife and I have had our work permits for Canada approved and we've received our letters however the VISA office hasn't mentioned anything about our kids VISA's.
Does the VISA office issue the VISA in the passport or is it something that will happen when we land in Canada?
Did you make TRV application for your child also?. A TRV visa should be stamped in the passports before arriving in Canada.
Read this portion in your Guide:
Do family members need to apply separately?
Your family members who also wish to visit Canada must apply by filling out their own temporary residence form (Temporary Resident Visa, study permit or work permit). However, you may send all family member application forms in the same envelope with only one payment receipt for the total amount. See the “Pay the Fee” section.
Your spouse or common-law partner and children must meet all the requirements for temporary residents to Canada.
If your family members wish to follow you to Canada at a later date, they must complete a separate application for admission.
May my children attend school?
Your accompanying children may attend school in Canada. You must apply for their study permit at the same time as your application. If they intend to join you later, they must obtain a study permit before coming to Canada.Do family members need to apply separately?
Your spouse or common-law partner and children must meet all the requirements for temporary residents to Canada.