Highly recommend to hire an immigration lawyer to help with the IAD appeal. Mind you, it is expensive but necessary at this stage. They can advise you moving forward
You should hire a lawyer. Is your son already a PR? Doesn’t appear that he is so you will need to resolve your PR status appeal before you can even attempt to sponsor your child. There are consequences if you don’t meet RO. Given that you appear to have been reported this is going to be a long process for both you and if you retain your PR for your child. Just a reminder that you will need to attempt to extend their status via visitor record after 6 months.