How many cats are too many?

A couple of weeks ago we looked at a kitten who wasn’t weaned yet in the hopes of helping our aging cat out with our newer juvenile cat. It new seems this kittens brother is also in play as they are moving and needs a home. This is almost like rescuing the other. My house is plenty large, and I have plenty of litter boxes. The old man actually doesn’t mind his grand-niece and sometimes even initiates paw boxing until her zeal for play gets too much. I am torn. Having two more wee kittens is kind of daunting. Do I have enough lap for them all?