If she and/or the adult male return, see if you can connect with a local TNR group which can trap, neuter/spay, ear tip and release them. Better than doing it yourself so the cats don't associate it with you, plus they may have donations to pay for it. When the cats come back, they'll continue to hold the local territory without reproducing further, and will live longer because of less physical stress. I assume they're too wild-minded to adopt.
My local one is Kitty Bungalow Charm School For Wayward Cats, which also sets up fostering for the kittens so they'll become adoptable, and finds farm and business jobs for cats who aren't afraid of people but don't want to be pets. Your local situation may be different but it's worth looking into.