I am so sorry that you and your children have lost Holly, I understand that the thought our your children grieving is heartbreak added to your grief.
I am not saying my approach is right for everyone but my children were so distraught when we lost their first ( my third) cocker very suddenly all my ideas of waiting for the grief to settle before getting a new puppy evaporated. My youngest was also four when we got Tigger, my oldest six and they were bereft. What we did was find a breeder with month old pups then made a very long drive to choose one. I went totally PUParazzi on the poor little thing and when we came home I printed the pictures and put them in a plastic pocket folder, my girls carried it at all times until a month later when we could pick up Charlie Brown. It didn't stop them crying for Tigger but it was comforting.
Now our poor Charlie has gone too and our hearts are mending with our new little Teddy.
