Option 1: If all dependents will be at the age of majority, 18/19above at the time application is processed, you can apply for open work permit for all. Meaning dependent is expected to contribute to household income and decision to request for POF may be discretionary based on officers assessment.
Option2: if you choose to apply for study permit for the dependent 18above of college/university going age, then, during the processing, officer may request for offer of admission from a DLI to process the study permit. In this case you may be ask to proof funds.
Option3: if dependent child applying for study permit is a minor, at primary or high schools, where tuition fee is free in public schools-elementary or high sch. Then you do not need to proof huge funds.
The operarional manual and guidance used by ircc officers doesn't require you to proof funds under.