How Many?!?

This is Mama Kitty. A number of years ago, she showed up at the house pregnant and was just the sweetest, most affectionate cat. She proudly showed her new kittens to my husband and me and then turned into the beast from hell.
She was the most protective mother cat I’ve ever seen. She tore you up just for looking at her or her kittens; I wore a coat and gloves into “her” room just to feed her. It was so bad that I planned to put her down after her kittens were weaned and adopted.
Then, she attacked my husband, who promptly threw her against the wall. She LOVED him after that incident. Seriously, he could reach down and grab a kitten with no problem from that time forward; she just sat there purring.
Then my sister started making me feel guilty for talking about putting her down. She would talk to me through the cat, saying things like, “Aw, I wish you didn’t have to die . . .” Sigh.
So, she stayed. But, I’m the only one she likes. None of the other 4 cats in the house. Not many people who come in. Although she tolerates my sister, who saved her, she occasionally attacks her, too. But, she reserves a special, intense dislike for my mom, her soon-to-be roommate. Because Mom can’t stand Mama Kitty.
Mom thinks my sister should have kept quiet and let me put Mama Kitty down. Mom would still like to put her down and threatens to do so every time she sees her. And, now, they will be together for 10 hours a day while I’m at work. Uh, oh. I asked Mom last night to promise not to hurt her. She said, “Death doesn’t have to hurt.”
Okay, then. This isn’t gonna be easy.
Again, I have 5 cats in the house. With 3 regulars and a few drop-in strays in the garage. Mom is coming with 2 more cats and a dog.
I don’t know how this will work. But, I’m sure it will be an adventure!