Nicole is especially hard to make because of the young age focus of models, its quite hard to get her to look as old as she is in the game, I didn't have much trouble with Irina.
there is a workaround though, it's actually what I done with the photo you mentioned, I used img2img and selected the face area, that way I could focus on writing only prompt for facial features.
here is what the original looked like
View attachment 2828453
(this probably came from one of her ahegaos)
another matter, I trained only using the face so the body isn't hers it belongs to the base model, there is a bit of work on tagging each picture, if a picture of a face needs up to 20 tags imagine how many tags the whole body would need.
but there is a room for improvement because I didn't use many tags and the pictures need more light, (the game is kinda night theme, so troublesome

)