There's an option in NovelAI that's been available for quite some time which you upload an image and with some good prompts you can make characters that isn't on their data (it also replicates the style of the uploaded image which is nice), so far I've tested on characters only and with default male companion (sfw and nsfw) and works great!
I do have to do more testing another day since I tried adding 2 characters like Nefer and Yelan in the same img but got a Yelan with Nefer face and kinda similar outfit, maybe adding 2 characters in the same base image or editing just one of them, I still need to mess around with it hehe.
That being said this is great since I'm now able to do more recent characters as long as I manage to find a good model for it and detailed prompts for the outfit/face😬