I had to sleep on my response. I'm not sure how JPII could have been the first pope to proclaim that animals have souls since the word "animal" comes from "anima" which means "soul". Maybe he was the first pope who felt the need to point out the obvious, I don't know. I think the Catholic Church has always taught that animals have natural souls because the soul is the "animating" principle of the body. A natural soul is not immortal however.
The basic argument that places companion animals in heaven is that God will deny us nothing that would contribute to our happiness. That at least keeps 70zillion mosquitoes out of heaven. Now that does give rise to the conundrum that compared to my children the cat means nothing so if the reasoning is based on what would make me happy the salvation of my children is guaranteed based on that alone. Wouldn't that make parenthood so much easier.
Even Father John Hardon makes allowances for the presence of pets in heaven based on the happiness of the heavenly resident. I'm not really inclined to argue with him but my jaw does drop in astonishment at what these kinds of ideas make of heaven.
Heaven is the beatific vision: the direct apprehension of the Glory of God, it is realized in the primary object Who is God Himself and the secondary object which is His glory reflected in His creation. The secondary object admits the possibility of our earthly pets but it does not require it.
Attempt to imagine every perfect experience of earthly existence: marriage proposal, wedding, birth of children, rapturous music, your favorite movie opening, that most enjoyable hobby, your greatest laugh, the most sublime moment of prayer, the realization that God loves you... every experience that engrosses, captures, uplifts, enlivens and excites. Wrap them all up into one event, then double it, and double it again and keep on doubling it until it's too much for the unaided human to even comprehend and we might be on the approach to understanding what it will be like.
I remember the first real date I had with my wife as we sat looking at each other while the food grew cold, well at least I was staring at her. I really don't know what she was doing but I do know no food was eaten that night. I thought "I could do this all night" but of course I couldn't do it all night because the restaurant eventually closed. I think that's the first time I wrapped my head around what heaven could possibly be like; the restaurant will never close and the object of my adoration will be inexhaustible.
I really don't see any room for cats in that. I remember a theology grad student telling me that heaven to her would be an eternity of studying books that she'd never had the chance to read in this life and I couldn't but wonder why anyone would want to read a book when the Author was available for an eternal interview.
I agree
To be in the presence of God will be sufficient for eternal joy..
I do like to think that our beloved 4 footed family members will have an opportunity to lay at the creators feet ...or in the case of fish to swim by on the river that flows through heaven