Off the top of my head the Biggest obvious point of comparison is the borough = eye colors thing which AFAIK isn't really a thing most petsites do/have done outside of just Flight Rising lmao. I think the lore reasoning for it was also a simple and generic "the elemental energy of the land influences the eye color" deal. But that's probably it tbh? Maybe what little we know of Fauna mechanics could be considered to be too similar to Familiars, but minipets aren't just a FR thing in fairness.

I think you're right that as of writing they're both very distinct now based on just what we can glean from the demo, but WRT future mechanics they might still pull some notes from FR. It's just my assumption based on what the game appeared to be like since before the Kickstarter.