The house can't be sold without court approval. A title insurance company will not issue title insurance, to a buyer, until the title has been changed, by a court, so that it's no longer in the name of your deceased father. Until then, if you don't pay the mortgage who will? If it goes unpaid for too long (3-4 months), the lender who holds the mortgage may commence foreclosure. If your state has a simple probate process, then you don't need a lawyer. Otherwise, you ought to get one. "...
Yes, but under the laws of your state, step-father may have the right to inherit a certain amount from your mother regardless of what the will says. But, "yes", she can create the POA and the Will without telling him.
Sorry to tell you this, but you're not going to get your son returned to you unless you hire an attorney to present a compelling case as to why (under the laws of your state) you should have your son back.
Even though you have no money for a lawyer, you need one if the estate has significant estate value (e.g., $30,000+) and you believe you are a beneficiary or heir. Many attorneys will help you (for no money up front) if they believe there is value in the estate and you are entitled to it. You can pay them on the back end of the case.
This is a very complicated area of the law. The only way you'll get good, solid information is by consulting with an attorney, in your community, in person. I know you want to get a cheap answer via AVVO, but if I were you I'd consult with an attorney. That may cost you $200-300, but then you'll know the correct answers as they apply to your family situation. Good luck.
If her will specifiies that certain things go to you and certain things go to your sister, and if there is proof that she owned the items in her own name, and not in joint ownership with your father, then the answer to your questions should be "yes." You should consult with a local attorney about accounting for the things in the SD box. Are you handling the probate without an attorney? I wouldn't if I were you.