Last night went about as well as can be expected. We had to teach the new brat that the "kitty crazies" are not appropriate on the bed. She got dumped off said bed maybe half a dozen times before she finally seemed to decide maybe we didn't want her attacking everything in sight. Then she curled up and slept through the night.
Today I left the house for a bit this morning, and my other half thought I had taken the kitten with me - I hadn't. So she didn't fuss at all while I was away. I came back to both cats nose to nose again, no hissing. Played with her some more, and Anubis started to watch with interest, and even ran past with his "monkey tail" once. He only curls his tail in that specific manner when he is playing. So we're making very fast progress, and I think they're going to do just fine tomorrow while we're both out out of the house (I have work, he has some errands to run).
So now it's just a matter of teaching her house rules, and calming my own anxiety. I'm one of those people who has issues with change, to the effect that my brain reads any new thing in the house as "scary", so it takes me some time to get used to a new furball. I did the same thing when Simba moved in years ago, so I know it will be okay, but that part of my brain refuses to listen to logic. Maybe it's part of why I understand animals so well. I know what throws them off, because the same things often bug me too.
My mother has dubbed the kitten "Nala", since she looks (and acts) a great deal like Simba. My sister suggested "Kiara" which I liked as well, but my other half put in his vote for Nala, so Nala she is.
Nala is starting to learn to entertain herself a bit, has discovered the "racetrack" (hallway) and has started to use it. She is figuring out what are toys, where she shouldn't go - though she does get curious about places if you are standing next to them. But hopefully this means she will wear herself out some while everyone's away at work, instead of sleeping all day and turning into a maniac at night. If Anubis decides to start playing with her a little too, that will help.