Congrats and good luck with the cats! I had a nightmare, but my cat was 16. We ended up having to fence our garden in half and separate the house with stair gates as my cat hissed and swiped at the puppy so the puppy wanted to chase and terrorise the poor old cat. I did manage to get them sit next to each other for treats, but as soon as the treat session was over war would begin again. Sadly my cat passed away (kidney and thyroid - not puppy). Loads of people on here have both without problems.