As you are the principal applicant you have to show the proof of funds.
After getting PR card (may take 4 to 6 weeks), you can go back and bring family together, before expiry of the medical date as your family has to land within the validity period.
If there is some un avoidable reasons for your dependants to stay further ( such as to complete the ongoing educaion/course) the principal applicant can land at an early date. The dependants can land within the validity period of their visa ( one year from date of medica). please ensure to retain their original CPR along with them.