I have a close friend that lost her Yorkie two years ago on Mother's Day. Her oldest son was playing baseball and the dog and the ball connected - freak thing that couldn't be replicated ever. She was devastated by the loss. However, they did end up with two more and where she loves them and it has helped I don't think you ever get over the devastation. And they are never replaced. I do suggest some sort of memorial or grieving item - I gave my friend one for each of her sons to put on their backpack with Sampsons name engraved. To this day, as a sophomore and an 8th grader, the keepsakes are still on their back packs.
This is the one I got but I know there are a lot to choose from.
Best of luck with the new babies! Sending you many prayers and hugs!