see if the funeral home has a website or information on helping children grieve death. When my mother passed away (my children were VERY close with her) we got something from them. You would really be amazed, because kids can understand so much at their age, but death... is something they just don't get right now. I was a little put off by the fact that my youngest (at the time - she was 7) didn't seem to even shed a tear... the information I got helped me understand the way she was processing the death of her "Mimi". my oldest - at 9, was devastated, and I was able to help her wit hher pain, by understand how she was processing the details.
If I were you, I would not explain it to the kids... if they ask about her when they are older, you can explain that she is no longer with us, and then the discussion of suicide can be touchy too... considering religion, not sure if that even comes into play here. I would stay home from the services, with your children. People may or may not judge you based on your absence, but your husband can explain 'she's home with the kids' and most level headed people would agree that is not the wrong place to be.
They just dont have the emotional range to understand this.
This is a great resource i just found... easy to understand table outline of each age, and how they are able to react. http://www.childgrief.org/documents/HowtoHelp.pdf
good luck, and I am very sorry for your family's loss. Suicide is especially hard, because we cannot make sense of it ourselves, and a certain amount of guilt that we didn't help is always a nagging emotion. I hope that you and your family can make it past this tough time. I had a friend commit suicide at 18... I still feel guilty that I didn't see the signs and reach out to her.