Blue particles are definitely the right choice for her, but the blue is in my opinion too strong for the skin, which is especially noticable on her ult.
So my advice is too make her blue particles slightly brighter and a bit more silverish.
In my opinion her Wing-colour and her clothing don't fit together at all, so I would make her wings look yellow and let her particles stay yellow like in her base skin.
**JUDGEMENT KAYLE **
I think the choice of colour is great, the only thing I would chance make her particles a bit darker to make it fit more to her outfit and wings.
The thing I'm missing here is that her particles should have some sort of electric sparks, since when I see this skin I just think of a technologic advanced Kayle who will attack you with some sort of electric poles.