We live in Illinois. My mom passed away 2 yrs ago, and before she died she drew up a will leaving her estate to my sister and I. She gave us a small house she owned prior to her marriage and what she had inherited from my grandparents. The estate did not go into probate. She also had marital property a home, the contents of the home, some mutual funds and a life insurance policy that we didn't receive. My step dad has now passed away, and has no will. His only heir is his sister. Do my sister and I have any rights to their marital property? We were also named as secondary beneficiaries on her life insurance policies.

Insurance policy goes to the person named in it, and does not go into probate. So if you were not listed on the policy you don't get the money.

If the step dad was co/owner of the property and it was deeded to him also, then it goes to him.
You if you had any rights it would have been to challenge in court at the mothers death.

You have no right to step fathers estate