Your pair of characters are very interesting. I like the backstories that you created for them, it's interesting and to me was done really well. The only thing that irks me, but not too much, is the curse about Jayde only turning at night. It's a strange curse, which I mean, would and could be possible, but for me I don't think that it would make sense to have it in.
I could see maybe Jayde losing a bit of control and possibly could change it to where she can now only transform with a beaststone because shifting on her own is hard or nearly impossible so having a source of harnessed Laguz energy might allow her to do it. That could be the curse, at least versus only changing at night and not in the morning like a werewolf.