Okay, so the reincarnation theory is pretty common, but this is what I think.

1. Moon and Clearsight

Okay, so both of these characters are pretty similar. Both of them can see the future and genuinely liked Darkstalker. Both are anxious and worrywarts, yet always rise to the occasion and prove themselves to be one of the bravest. I really don't need to explain, if you've read the books.

2. Turtle and Fathom

Green. Seawings. Princes. Animus. Worried about their power. Ignored. Hyper girlfriends. Look EXACTLY the same. Nothing else needs to be said.

3. Kinkajou and Listener/Indigo

Honestly I think Kinkajou was a mix of these two characters. She was there for Moon and helped her in the exact same way Listener helped Clearsight. And I need not speak about the instant and multitude of crushes. Even if she didn't have as many, she sure was up for dating Winter in the beginning. At the same time she played Indigo's role and helped Turtle out of his shell, becoming his love interest as well. 

4. Winter and Prince Arctic

Okay these guys are pretty much alike. Of course Arctic in the beginning rather than Arctic towards the end of the book. Both of them were told they were nothing since the beginning, they both struggled with the whole Icewing system. Both were princes and both left their tribe in the end. They both did fall in love with a Nightwing, but Moon wasn't Foeslayer and there was someone else more like her. 

5. Anemone and Pearl/Albatross

Anemone was a lot like Pearl. She did care but had a sorta self absorbed/aristocratic behavior.  As for why I wrote Albatross up there, they both had 'weirdly colored scales' and went a little crazy with their powers. Thankfully, Anemone was able to 'recover'

6. Lynx and Foeslayer

Now, this may be my Lynxter side speaking but if you look at it, Lynx is a lot like the Foeslayer we see in the prologue and Runaway. Both are energetic (don't know how else to say it) and don't criticize Arctic/Winter. But because we don't know much about Lynx I'm gonna end this here. Just, try to see this with an open mind, even if you're a Winterwatcher.

7. Qibli and Darkstalker (and me)

These guys. Like seriously. Both have almost the same ideas on how to use Animus magic. Like enchanting someone to like them a bit? Both are intelligent and the only difference is that Qibli wouldn't really go mad with power and will probably know where to draw the line. Unlike me, let's just all be happy I'm not an animus. *Cough* sorry, forget that ever happened. The bottom line is that if Darkstalker was a Sandwing without powers and had a little bit more of some moral and common sense, he'd be Qibli. 

Tell me if I missed something or if there is anyway I can improve my points.