Your rights are governed by the documents naming you as executrix - you need to talke to two attorneys, first the one who drafted your mother's estate planning documents and second the attorney handling the divorce. I'm assuming they were legally separated before she passed and before the divorce was finalized, but the effect of her death on her estate and divorce will turn largely on the documents drafted by the attorneys working with her.
You need to have an attorney file a probate on your mother's estate if you are named in her will. Until the divorce was final, they were still married. Grandmother died, so who got her stuff? Mother? If so, it would be included in mother's estate and be her separate property. If there is a will, then mother's estate would have a claim for the value of the stuff taken and the estate would need to go after stepdad for value of stuff taken and half of community interest in assets. Estate, not you, would be responsible for any valid claims. Many creditors will settle for les than what is owed too. Forget talking to 2 different lawyers. Have the estate hire an attorney to probate your mother's estate. you can also go to courthouse and get sopies of any final orders in the divorce, if there were any. Sounds like you have a copy of her will. In the probate, you will be issued letters of administration which give you authority to act on behalf of the estate. Until then, you don't have authority to act. Once obtained, if stepdad took stuff he wasn't entitled to, you can report the theft. I'd hold off on that until you talk to a probate attorney though.
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