I had a cat named Isis for very nearly 14 years. She looked the total opposite: all black except for some white on her chest and belly. Another opposite: instead of being the mother, she was the daughter of my eldest cat who survives her. (My Isis passed away of cancer a few years ago. I wish your Isis only the best of health!) Also, a cat and her three kittens showed up at our house about 8 years ago. We gave one away and kept the mother, Sophie, and her 2 boys. It seemed like a shock going suddenly from having two cats to having 5, but it all worked out and we love them like crazy! I know not everyone can keep that many cats; of course, everyone's situation is different, but I just thought I'd let you know that it can work out and 5 doesn't seem excessive after all. When our Isis tragically left us, we were already used to having 5 that a year or more later, we adopted another cat from the shelter.
Enjoy your Isis and her beautiful, blue eyes! I'm glad you found such a good shelter for her kittens!