Not QUITE, but it's sort of like how soulmates are supposedly like. They can pretty much read each other's thoughts, and when one of them is in pain, it's pretty painful for the other. Anahera getting knocked out gave Atarangi a pretty bad headache, but you'll see in the next chapter that they'll be fine. Nivena kind of likes them, so she didn't hit Anahera that hard.
They'll probably come off as similar because they grew up in generally the same way so they have the same values. Traits-wise, however, there's a bit of a difference. I'm sad to say that Ciardah at least, won't have much development until arc 2, due to Nivena being the protag, and her... special circumstances.
Key 19 is at that point where I know where I want to go, but can't quite get there. There will probably be updates this summer, but don't expect me to hit my stride until at least three chapters pass.

Then again I shouldn't be talking, since I haven't updated my story since last July.

Best of luck.