I'm of course happy that kittens got a home, but kittens are not an answer to all your problems. It seems like an emotional decision made in an emotional state.

Kittens aslo don't stay kittens for long. I hope you are doing a long, slow integration. Adding a 3rd and 4th cat can really effect 'cat dynamics' in your home, EVEN if they seem to be getting along right now, it may not be the case in the future.

My 2 cents.

Best of luck with your girls,