Café de Nuit

https://en.m.wikipedia.org/wiki/Grimalkin

How did I miss this? I knew about the tavern names a clever grey Malkin, but I somehow missed the fact that that could actually be a word in English, or at least Old English?

Yup, I'm pretty sure that's the source for all the cat stuff in NV. (Sekmhaa, Plains Cats, etc.) I guess we're to assume that Malken (whatever origin you like) took his name from his fondess of cats, or thinking himself catlike in his behavior. Then as a darklord, the domain's cat associations came from there, with the DP's matching the domain to his personality.