As the reddish backlight is from the gelled flash in the fireplace, it technically might be reproducible. But if I don't use the main flash, I'd have to increase the ambient without having to push the exposure so much afterwards. Would that change the balance of the light from the gelled flash? I don't know. I may have to try... If the cat will pose again
I might be able to increase the power of the gelled flash, or take it out of the fireplace and use it directly as a backlight.