This is how Gaia would look if she was at the same level of spirit level as her brothers.

Here's a little explanation:

When the wolf siblings were born their fur colors were a bit different due the their mortal father. When Sol was a pup he was more of a rusty reddish brown color and Artemis was more of a silver and white pup. As they got older and their powers began to develop and evolve their fur colors slowly changed to their current state.

Also, their fur also represents how much spirit power the have which indicates who's the strongest. Sol has the most spirit power being 75% spirit & 25% mortal. Sure his vibrant red fur and bright yellow markings aren't exactly practical for hunting, but does that really matter when he can set an entire forest on fire in less than 5 minutes, summon a monstrous thunderstorm, and bring upon a drought that last for as long as he chooses ?? I don't think so.

Artemis on the other hand has a dark blue coat. It still seems like he would stick out, but in the night you would never know he's there or in the deep ocean. Combine this with his manipulation of moonlight and he'd look like nothing more than a few scattered moonbeams. His blue coat also makes him more calming to look at which allows you to fall asleep more easily and allow him to enter your dreams.

Gaia developed her powers much later than her brothers, and since she's only 25% spirit and 75% mortal it takes a long time for her to show any physical changes. The vines on her neck and tail took at least a year to appear on her after she discovered her abilities.

So, Will Gaia ever look like this ? Well, If she really tried and focused on developing her powers to be at about the same level as her brothers than yes she could, but as of currently sh seems to be pretty content with her position. Of course the future Isn't set in stone~

(Hopefully I kinda explained this little piece of lore well xP but let me know what you think of Neo Gaia :3)