I didn't know you had named Gray's dad Rockfall! What meaning does that name have? you said - fall meant that the cat's appearance or behavior imitates his prefix. And did Sleettail (Windflight) have windclan blood on them like in Canon? Maybe I'm mistaken but I remenber Windflight being... Thistleclaw's dad? Not sure!
"Rockfall" as a name referred to a tom who was steadfast, quiet and not a little stoic - completely unlike his son! Greypaw got his casual personality from his mother, who was a purebred ThunderClanner in this world. She was very friendly and encouraging of her son's confidence before she died.
Due to the nature of genetics, family sizes and timeline issues, a LOT of characters and their families have been moved around and changed. It might as well be an entirely new universe! Lynx's been super hard at work arranging and rearranging in the background to make sure everyone's families and colors make sense. Any new stuff will be clarified as asked.