She sounds like a Splash but pictures of them would help. If she is splash mating her to a blue rooster would give you about 50% Splash and 50% Blue offspring. I wouldn't advise crossing the Partridge with the Light Brahmas. @Amer could probably tell you what the result from that would be though.
Posting pictures of them would be super helpful, but you're saying you have a Blue Partridge male, a Light (Columbian) hen, and another hen that is Splash Partridge? Or Blue Partridge? She cannot be both.