Before her "canonical" appearance in the short novel Sain Seiya Golden Age,
the minor goddess Astraea had a brief showing in Sakamihara 's doujinshi "Zeus Chapter" .
She was in a couple of illustration and in the short gaiden about Faust de Mars.
When I compared her with Kuori 's drawing I found a convincing resemblance, imho.
Knowing that ms Kuori is one of the artist who make more references to other media besides kurumanga (TV series, movie, games ... ),
could she might have taken inspiration from something unofficial; but I think it's well in saint seiya fandom ??