It’s not unknown for a mother cat to adopt and raise puppies–but at the same time as her full litter of kittens? Isn’t that asking rather a lot?
It reminds me of a mouse I had, named Sleepy, who had an enormous litter of babies who simply refused to be weaned. They’d mob her and wind up carrying her around as they nursed her. She soon realized that the only thing she could do was jump on top of the water bottle, out of their reach, and chatter at them angrily.
This cat needs to do that, too.