Let me see if I can put together Lucky’s hints that were laid out so nicely by Obius - thank you, Obius!

I believe this may be Lucky’s kitty, and here is why I think that:
1. Non existent. This kitty would not exist in the real world. We are lucky that these kitties don’t have to be real.
2. Has some gradient. There looks like there is a little gradient, but not as obvious as others are.
3. Spies on colors and colors are important. This kitty’s coloring is very unique and is made to easily distinguish between the upper and lower parts of the body, and the very unique eyes.
4. Easily impressed by things. This is a pps, and usually the younger a kitty is, the more easily things impress them or catch their attention.
5. Loves to splash and play tag. Being young, this kitty probably loves to splash around in the water and loves tag, but at a young age would not be the most athletic yet.
6. The favorite snacks are chocolate chip cookies, mango, icecream, ginger ale, and hot cocoa - as a kid, I loved these foods.
I still like these foods even as an adult!7. Likes both night and day due to how different the ocean is during the night and day - not only does this kitty look like night and day, which would affect the ocean differently, the blue layer between the upper day and lower night looks like a layer of water.
8. Lastly the big cat reference. This interest was more for all wildcats, and this kitty, though it does not look like any wildcat in real life, looks very wild and free, and pretty.
So perhaps I’m way off, but it was fun giving it a shot! And since rockruff claimed the selkie, we have to look elsewhere to figure out your kitty!