Suigintou's eyebrows, they're more than just a line in the original, they are distinct patches of her grey hair: i.imgur.com/qjbWTNr.jpg
Her eyes in the above pic have more detailed colouring, thicker black around the iris, the iris itself is pink and purple etc.
Suigintou's right wing (left from our perspective) has some colour bleed from Jun's trousers.
Optional: In the example pics Suigintou's wings have grey highlights making them more 3D, up to you, just mentioning it.
Once the colouring is finalised I'll start specing up the 2013 version (as long as thats OK with you ofc).