We're in almost exactly the same boat. We had too many cats about the same age, and lost two to normal failures of old age and one to cancer, within the last year. Now we have one very spoiled 14-year-old neutered female calico, who seems to think being an only cat is great because she has a lock on the spot between us in the bed. We plan to get at least one new member this spring. But we'll take our time to find a compatible individual.

You can count on the old cat being really angry for a few days. Then the new cat will become an adopted child at best, or part of the background to be ignored, at worst.

Don't limit it to kittens. Kittens can always get 'dopted. Cute is an evolved survival trait. But you don't have a kitten for very long in any event. The shelters all have young, healthy adults that it's harder for them to find homes for.

Peter.