Try not to do the what-ifs. It will just be unbearable to keep reliving the situation. We know you did the best you could and loved them even though you didn't have time with them. RIP little babies
I was hoping you were going to say you would be getting another pup. I think it's a good idea to save the names too, then the new one/s can be in memory of your little angels. And I think it's only right for them to be buried in their home. Just be sure to take some pictures of their grave so you can remember it.