We have hit evening of day one.
Though there is still some hissing going on, the kitten is doing a very good job of listening when Anubis warns her off. And he is doing a very good job of allowing her some shared space. She may not go to his chicken bowl, she may NOT sit on his spot on the cedar chest (hoo boy did he not like that), but the regular food bowl in the kitchen, he not only let her eat from, he snuck around the corner to sniff at her tail like he used to with Simba when they were first getting to know one another.
On that note, I am seriously thinking of taking my grandparents suggestion (made in separate conversations no less) to just dub her Simba 2. I've slipped into calling her Simba anyway, and it feels right. They say cats have 9 lives anyway, so who knows?
She's curled up on the couch now, purring away. She seems to be trying to sit in places where she smells that other kitties have sat before. I couldn't figure out why she was insistent on being allowed on James's nightstand, until he told me Anubis has been sitting on it (even when told not to - whoops) so - she smells kitty there, therefore she assumes it's okay to sit there. That also explains why she refused to be deterred from sitting on Gram's table tonight (I ended up having to distract her with string).
Gram discovered she likes plain old yarn (she snubbed the other string-y things I tried to offer her). And it seems those crinkly sparkle balls she also likes - the ones made of cellophane.
Hopefully she and Anubis can get their differences worked out here soon. If Monday rolls around and we're still not sure of it, we're just going to have to clear out one of the bathrooms enough to let her plop in there with a litter box and some food and water since we'll both be out of the house. But if things progress as quickly as they have thus far, they may actually be fine that soon.