@dlowan,
Sometimes animals will surprise you.
I lived for 15 years with three cats that absolutely hated each other so I was worried about introducing a new cat to Biscuit (cat (old, murderous)) and Diamond (dog (young, exuberant)) when a neighbor showed up pleading for me to give a cat a home.
But Godzilla fit right in. Now they all cuddle up to each other.
I would have never dreamed it was possible.
I'm keeping my fingers crossed for you.