Okay, so sandglass took pity on me (I've been awake nearly twenty four hours) and reread Apollodorus for me to get to the bottom of Andromeda's ancestry!

Sandglass sez: It looks like Andromeda's dad is 3/4 Egyptian (1/2 God 1/2 Greek grandfather, Egyptian grandmother, 1/2 Egyptian 1/4 Greek 1/4 God father, Egyptian mother).

We couldn't find anything really on her mom who was kind of a non-entity besides pissing Poseidon the fuck off, so she could be anything.

So I guess the short answer on Andromeda is 'kinda brown probably, could be black if her mom was'.

I also found an ancient greek urn with a picture of a white Andromeda being tied up by two black Ethiopians, but while that's as close to the source as you can get, it's about the same as how some people draw Gambit big and muscular and others draw him as fragile as a cherryblossom, so you can choose to incorporate that or disregard how you please.

THANK YOU FOR YOUR TIME.