We just lost our hamster. She was not gone when I found her in her cage. Surprisingly, at 40 I was broken hearted and my daughter was handling it well. My mom came in with a soft baby blanket, put Bambi, our hammy, in it and talked gently to her. She told her we love her and she can let go, she can go see her mommy in heaven. It helped even at this age for my mom to show me that the last thing a pet hears should not be crying, it should be gentle and loving words.
After she passed, we buried her in the front garden in a lovely box with a beautiful handerchief. We told her again we loved her and asked God to look after her. We said we hope that she is happy and we will miss her.
My daughter is 12 and it helped her through the transition. We still talk about her and the funny things she used to do. We keep her memory alive and try to get to a place where death is not scary, just a transition.
I'm sorry to hear about your lost pets. Sending hugs your way.