Z-image: Use strenght 0.5-0.8, start prompt with 'EvaKiss_style, Digital illustration of a' ... 0.5-0.6 mostly times is better. Sometimes it will contain more or less realistic parts of an image; this is part of the realist art style, but during generation it doesn't always fit well. And sometimes it doesn't apply the style at all for no reason.

Pony: I recommend using the latest version. The strength 0.9 is well for most cases. Backgrounds and characters could have different styles, original authors of characters and backgrounds are different people, also it depends on additional LORAs. Put 'photo, render, 3d, cgi' in negative. Adetailer is required for better results, specially eyes and hands.

18.06. update for v1.3. Using trigger Eva_kiss has slight effect on eyes, making them appear somewhat closer to the original.