On step families....it's hard. Very hard. When the family member who bonded the two families together dies, it's difficult to redefine relationships, isn't it?
I am the step mother. DH had two children before we married and they were never like my children. His DD is only 11 years my junior and his son is 15 years younger. His DD moved out the first year we were married and we never got along. Ever. I helped raise his son and we had a good relationship but it was always "Chris' son" and I was "Chris' wife". I love my stepson, but not as a son, does that make sense? When my DH passed away last year, we talked and cried together, I felt closer to him than I had in years. I have invited them to my house a few times and they have never come. He has never collected any artifacts or items from his childhood that we saved over the years. I have them ready for him and thought he would like to have them. He told a mutual friend it's too "weird" to come to my house without his dad here. I did have dinner with his son and family at Christmas time. It was kind of awkward, but I am glad I made the effort. And no, I do not consider his grandkids my grandkids. It's just the way it always was and still is. His kids were always jealous of Bree and never liked her. Like I said, it is very hard and we all do the best we can do.
I also had a step mother who passed away (she and my dad were married 35 years). Both sides of the family got together for the service and we reminisced like we were kids again, but we don't keep in touch now. They rarely contact my dad. It's a divided family.
So, don't be upset Laurie. Every family member feels differently and we all adjust somehow. You and your family loved her and are mourning her loss. You cannot be responsible for their feelings. Hugs and pixie dust to you.

I am so sorry for your loss.