I once heard Billy Graham answer the question about dogs and Heaven. I liked his answer, so I am sure it is the correct one.
Anyway, here is Dr. Graham's point, possibly a bit less than artfully condensed. A caller who had just lost his dog that was his much-loved companion for many, many years was devastated and asked him if he could hope to see his dog again in Heaven. The reply was that his understanding of Heaven is that anything that makes us happy, that would make our existence there more pleasurable, of course would be there. If our dogs make us happy - they WILL be there.